diff --git a/CHANGELOG.md b/CHANGELOG.md
index ae7eacf9..6b9ff897 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -78,6 +78,8 @@ This release closes the [3.0.0 milestone](https://github.com/Instagram/IGListKit
 
 - Added `IGListGenericSectionController` to take advantage of Objective-C (and Swift) generics and automatically store strongly-typed references to the object powering your section controller. [Ryan Nystrom](https://github.com/rnystrom) (tbd)
 
+- Added a debug option for IGListKit that you can print to lldb via `po [IGListDebugger dump]`. [Ryan Nystrom](https://github.com/rnystrom) [(#617)](https://github.com/Instagram/IGListKit/pull/617)
+
 ### Fixes
 
 - Gracefully handle a `nil` section controller returned by an `IGListAdapterDataSource`. [Ryan Nystrom](https://github.com/rnystrom) [(#488)](https://github.com/Instagram/IGListKit/pull/488)
diff --git a/IGListKit.xcodeproj/project.pbxproj b/IGListKit.xcodeproj/project.pbxproj
index ce07b8c5..e72c0385 100644
--- a/IGListKit.xcodeproj/project.pbxproj
+++ b/IGListKit.xcodeproj/project.pbxproj
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@@ -405,6 +434,21 @@
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+				290DF3601E930D05009FE456 /* IGListBatchUpdateData+DebugDescription.h in Headers */,
 				0B3B92D01E08D7F5008390ED /* IGListExperiments.h in Headers */,
 				296AC95C1EA518D3005137E2 /* IGListReloadIndexPath.h in Headers */,
 				0B3B93321E08D7F5008390ED /* IGListAdapterUpdaterInternal.h in Headers */,
@@ -941,6 +1012,7 @@
 				0B3B92CA1E08D7F5008390ED /* IGListDiff.h in Headers */,
 				0B3B933A1E08D7F5008390ED /* IGListSectionMap.h in Headers */,
 				0B3B92DE1E08D7F5008390ED /* IGListMoveIndex.h in Headers */,
+				290DF35C1E930CED009FE456 /* IGListAdapter+DebugDescription.h in Headers */,
 				0B3B92CE1E08D7F5008390ED /* IGListDiffable.h in Headers */,
 				29DA5CA01EA7C70400113926 /* IGListGenericSectionController.h in Headers */,
 				0B3B92EA1E08D7F5008390ED /* IGListMoveIndexInternal.h in Headers */,
@@ -962,6 +1034,7 @@
 				297278BD1E6B58560099D8EA /* IGListBatchUpdates.h in Headers */,
 				0B3B92FE1E08D7F5008390ED /* IGListAdapterUpdater.h in Headers */,
 				0B3B93141E08D7F5008390ED /* IGListScrollDelegate.h in Headers */,
+				290DF3581E930CE2009FE456 /* UICollectionView+DebugDescription.h in Headers */,
 				0B3B93261E08D7F5008390ED /* IGListUpdatingDelegate.h in Headers */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -1318,26 +1391,33 @@
 				0B3B92F51E08D7F5008390ED /* NSString+IGListDiffable.m in Sources */,
 				0B3B93011E08D7F5008390ED /* IGListAdapterUpdater.m in Sources */,
 				29DA5CA51EA7C75500113926 /* IGListGenericSectionController.m in Sources */,
+				294652B31EA927440063BDD9 /* IGListSectionMap+DebugDescription.m in Sources */,
 				0B3B92D91E08D7F5008390ED /* IGListIndexSetResult.m in Sources */,
+				294652AF1EA927440063BDD9 /* IGListAdapter+DebugDescription.m in Sources */,
 				0B3B93431E08D7F5008390ED /* IGListWorkingRangeHandler.mm in Sources */,
 				0B3B92F11E08D7F5008390ED /* NSNumber+IGListDiffable.m in Sources */,
 				298DDA221E3B0DC800F76F50 /* IGListCollectionViewLayout.mm in Sources */,
+				294652B51EA9275A0063BDD9 /* IGListDebuggingUtilities.m in Sources */,
 				0B3B93311E08D7F5008390ED /* IGListAdapterProxy.m in Sources */,
+				294652B01EA927440063BDD9 /* IGListAdapterUpdater+DebugDescription.m in Sources */,
 				0B3B92CD1E08D7F5008390ED /* IGListDiff.mm in Sources */,
 				297278C11E6B58560099D8EA /* IGListBatchUpdates.m in Sources */,
 				0B3B931F1E08D7F5008390ED /* IGListSingleSectionController.m in Sources */,
 				296AC9601EA518D3005137E2 /* IGListReloadIndexPath.m in Sources */,
+				294652B21EA927440063BDD9 /* IGListDebugger.m in Sources */,
 				0B3B92D51E08D7F5008390ED /* IGListIndexPathResult.m in Sources */,
 				0B3B93371E08D7F5008390ED /* IGListDisplayHandler.m in Sources */,
 				0B3B92E11E08D7F5008390ED /* IGListMoveIndex.m in Sources */,
 				0B3B93471E08D7F5008390ED /* UICollectionView+IGListBatchUpdateData.m in Sources */,
 				0B3B92E51E08D7F5008390ED /* IGListMoveIndexPath.m in Sources */,
 				DAA83ACF1E8ECE06000F6810 /* IGListAdapter+UICollectionView.m in Sources */,
+				294652B11EA927440063BDD9 /* IGListBatchUpdateData+DebugDescription.m in Sources */,
 				0B3B933D1E08D7F5008390ED /* IGListSectionMap.m in Sources */,
 				0B3B92F91E08D7F5008390ED /* IGListAdapter.m in Sources */,
 				0B3B93191E08D7F5008390ED /* IGListSectionController.m in Sources */,
 				0B3B93131E08D7F5008390ED /* IGListReloadDataUpdater.m in Sources */,
 				0B3B93231E08D7F5008390ED /* IGListStackedSectionController.m in Sources */,
+				294652B41EA927440063BDD9 /* UICollectionView+DebugDescription.m in Sources */,
 				298DD9CB1E3ACFE300F76F50 /* IGListBindingSectionController.m in Sources */,
 				0B3B92C91E08D7F5008390ED /* IGListBatchUpdateData.mm in Sources */,
 			);
@@ -1406,28 +1486,35 @@
 			buildActionMask = 2147483647;
 			files = (
 				0B3B92F41E08D7F5008390ED /* NSString+IGListDiffable.m in Sources */,
+				290DF3591E930CE2009FE456 /* UICollectionView+DebugDescription.m in Sources */,
 				0B3B93001E08D7F5008390ED /* IGListAdapterUpdater.m in Sources */,
 				29DA5CA11EA7C70400113926 /* IGListGenericSectionController.m in Sources */,
+				290DF3711E931457009FE456 /* IGListSectionMap+DebugDescription.m in Sources */,
 				0B3B92D81E08D7F5008390ED /* IGListIndexSetResult.m in Sources */,
 				0B3B93421E08D7F5008390ED /* IGListWorkingRangeHandler.mm in Sources */,
 				0B3B92F01E08D7F5008390ED /* NSNumber+IGListDiffable.m in Sources */,
 				298DDA211E3B0DC800F76F50 /* IGListCollectionViewLayout.mm in Sources */,
 				0B3B93301E08D7F5008390ED /* IGListAdapterProxy.m in Sources */,
 				0B3B92CC1E08D7F5008390ED /* IGListDiff.mm in Sources */,
+				290DF3651E930D25009FE456 /* IGListAdapterUpdater+DebugDescription.m in Sources */,
 				297278BF1E6B58560099D8EA /* IGListBatchUpdates.m in Sources */,
+				290DF3751E931B57009FE456 /* IGListDebuggingUtilities.m in Sources */,
 				0B3B931E1E08D7F5008390ED /* IGListSingleSectionController.m in Sources */,
 				296AC95F1EA518D3005137E2 /* IGListReloadIndexPath.m in Sources */,
 				0B3B92D41E08D7F5008390ED /* IGListIndexPathResult.m in Sources */,
 				0B3B93361E08D7F5008390ED /* IGListDisplayHandler.m in Sources */,
 				0B3B92E01E08D7F5008390ED /* IGListMoveIndex.m in Sources */,
 				0B3B93461E08D7F5008390ED /* UICollectionView+IGListBatchUpdateData.m in Sources */,
+				290DF3551E930C89009FE456 /* IGListDebugger.m in Sources */,
 				0B3B92E41E08D7F5008390ED /* IGListMoveIndexPath.m in Sources */,
 				DA5F484C1E8E9D7000DAE6DA /* IGListAdapter+UICollectionView.m in Sources */,
 				0B3B933C1E08D7F5008390ED /* IGListSectionMap.m in Sources */,
 				0B3B92F81E08D7F5008390ED /* IGListAdapter.m in Sources */,
 				0B3B93181E08D7F5008390ED /* IGListSectionController.m in Sources */,
+				290DF3611E930D05009FE456 /* IGListBatchUpdateData+DebugDescription.m in Sources */,
 				0B3B93121E08D7F5008390ED /* IGListReloadDataUpdater.m in Sources */,
 				0B3B93221E08D7F5008390ED /* IGListStackedSectionController.m in Sources */,
+				290DF35D1E930CED009FE456 /* IGListAdapter+DebugDescription.m in Sources */,
 				298DD9CA1E3ACFE300F76F50 /* IGListBindingSectionController.m in Sources */,
 				0B3B92C81E08D7F5008390ED /* IGListBatchUpdateData.mm in Sources */,
 			);
@@ -1440,6 +1527,7 @@
 				298DDA391E3B168F00F76F50 /* IGLayoutTestItem.m in Sources */,
 				88144F1C1D870EDC007C7F66 /* IGTestStackedDataSource.m in Sources */,
 				88144F181D870EDC007C7F66 /* IGTestDelegateController.m in Sources */,
+				290DF3771E9323E6009FE456 /* IGListDebuggerTests.m in Sources */,
 				298DDA3A1E3B16F600F76F50 /* IGLayoutTestDataSource.m in Sources */,
 				88144F0D1D870EDC007C7F66 /* IGListDisplayHandlerTests.m in Sources */,
 				298DDA141E3AE3F300F76F50 /* IGTestDiffingDataSource.m in Sources */,
diff --git a/Source/Common/IGListMacros.h b/Source/Common/IGListMacros.h
index 23c3b1ff..b464be3a 100644
--- a/Source/Common/IGListMacros.h
+++ b/Source/Common/IGListMacros.h
@@ -24,3 +24,7 @@
 #else
 #define IGLKLog( s, ... )
 #endif
+
+#ifndef IGLK_DEBUG_DESCRIPTION_ENABLED
+#define IGLK_DEBUG_DESCRIPTION_ENABLED DEBUG
+#endif // #ifndef IGLK_DEBUG_DESCRIPTION_ENABLED
diff --git a/Source/IGListAdapter.m b/Source/IGListAdapter.m
index 4382bac9..791f1459 100644
--- a/Source/IGListAdapter.m
+++ b/Source/IGListAdapter.m
@@ -14,6 +14,7 @@
 #import <IGListKit/IGListSupplementaryViewSource.h>
 
 #import "IGListSectionControllerInternal.h"
+#import "IGListDebugger.h"
 
 @implementation IGListAdapter {
     NSMapTable<UICollectionReusableView *, IGListSectionController *> *_viewSectionControllerMap;
@@ -51,6 +52,8 @@
 
         _updater = updater;
         _viewController = viewController;
+
+        [IGListDebugger trackAdapter:self];
     }
     return self;
 }
diff --git a/Source/IGListAdapterUpdater.m b/Source/IGListAdapterUpdater.m
index 16d46ff3..75003eec 100644
--- a/Source/IGListAdapterUpdater.m
+++ b/Source/IGListAdapterUpdater.m
@@ -155,6 +155,7 @@ static NSArray *objectsWithDuplicateIdentifiersRemoved(NSArray<id<IGListDiffable
     };
 
     void (^executeCompletionBlocks)(BOOL) = ^(BOOL finished) {
+        self.applyingUpdateData = nil;
         self.state = IGListBatchUpdateStateIdle;
 
         for (IGListUpdatingCompletion block in completionBlocks) {
@@ -176,17 +177,14 @@ static NSArray *objectsWithDuplicateIdentifiersRemoved(NSArray<id<IGListDiffable
     }
 
     IGListIndexSetResult *result = IGListDiffExperiment(fromObjects, toObjects, IGListDiffEquality, self.experiments);
-    
-    // set the update data inside the update block. capture outside its scope to reference if an exception is thrown
-    __block IGListBatchUpdateData *updateData = nil;
 
     void (^updateBlock)() = ^{
         executeUpdateBlocks();
 
-        updateData = [self flushCollectionView:collectionView
-                                withDiffResult:result
-                                  batchUpdates:self.batchUpdates
-                                   fromObjects:fromObjects];
+        self.applyingUpdateData = [self flushCollectionView:collectionView
+                                             withDiffResult:result
+                                               batchUpdates:self.batchUpdates
+                                                fromObjects:fromObjects];
 
         [self cleanStateAfterUpdates];
         [self performBatchUpdatesItemBlockApplied];
@@ -195,7 +193,7 @@ static NSArray *objectsWithDuplicateIdentifiersRemoved(NSArray<id<IGListDiffable
     void (^completionBlock)(BOOL) = ^(BOOL finished) {
         executeCompletionBlocks(finished);
 
-        [delegate listAdapterUpdater:self didPerformBatchUpdates:updateData collectionView:collectionView];
+        [delegate listAdapterUpdater:self didPerformBatchUpdates:(id)self.applyingUpdateData collectionView:collectionView];
 
         // queue another update in case something changed during batch updates. this method will bail next runloop if
         // there are no changes
@@ -218,7 +216,11 @@ static NSArray *objectsWithDuplicateIdentifiersRemoved(NSArray<id<IGListDiffable
             }];
         }
     } @catch (NSException *exception) {
-        [delegate listAdapterUpdater:self willCrashWithException:exception fromObjects:fromObjects toObjects:toObjects updates:updateData];
+        [delegate listAdapterUpdater:self
+              willCrashWithException:exception
+                         fromObjects:fromObjects
+                           toObjects:toObjects
+                             updates:(id)self.applyingUpdateData];
         @throw exception;
     }
 }
diff --git a/Source/Internal/IGListAdapter+DebugDescription.h b/Source/Internal/IGListAdapter+DebugDescription.h
new file mode 100644
index 00000000..ab095bdb
--- /dev/null
+++ b/Source/Internal/IGListAdapter+DebugDescription.h
@@ -0,0 +1,16 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <IGListKit/IGListKit.h>
+
+@interface IGListAdapter (DebugDescription)
+
+- (NSArray<NSString *> *)debugDescriptionLines;
+
+@end
diff --git a/Source/Internal/IGListAdapter+DebugDescription.m b/Source/Internal/IGListAdapter+DebugDescription.m
new file mode 100644
index 00000000..60b4fdb7
--- /dev/null
+++ b/Source/Internal/IGListAdapter+DebugDescription.m
@@ -0,0 +1,75 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "IGListAdapter+DebugDescription.h"
+
+#import "IGListAdapterInternal.h"
+#import "IGListSectionMap+DebugDescription.h"
+#import "IGListAdapterUpdater+DebugDescription.h"
+#import "UICollectionView+DebugDescription.h"
+#import "IGListDebuggingUtilities.h"
+
+@implementation IGListAdapter (DebugDescription)
+
+- (NSString *)debugDescription {
+    NSMutableArray *lines = [NSMutableArray arrayWithObject:[NSString stringWithFormat:@"IGListAdapter %p:", self]];
+    [lines addObjectsFromArray:IGListDebugIndentedLines([self debugDescriptionLines])];
+    return [lines componentsJoinedByString:@"\n"];
+}
+
+- (NSArray<NSString *> *)debugDescriptionLines {
+    NSMutableArray *debug = [NSMutableArray new];
+#if IGLK_DEBUG_DESCRIPTION_ENABLED
+    [debug addObject:[NSString stringWithFormat:@"Updater type: %@", NSStringFromClass(self.updater.class)]];
+    [debug addObject:[NSString stringWithFormat:@"Data source: %@", self.dataSource]];
+    [debug addObject:[NSString stringWithFormat:@"Collection view delegate: %@", self.collectionViewDelegate]];
+    [debug addObject:[NSString stringWithFormat:@"Scroll view delegate: %@", self.scrollViewDelegate]];
+    [debug addObject:[NSString stringWithFormat:@"Is in update block: %@", IGListDebugBOOL(self.isInUpdateBlock)]];
+    [debug addObject:[NSString stringWithFormat:@"View controller: %@", self.viewController]];
+
+    if (self.registeredCellClasses.count > 0) {
+        [debug addObject:@"Registered cell classes:"];
+        [debug addObject:[self.registeredCellClasses description]];
+    }
+
+    if (self.registeredNibNames.count > 0) {
+        [debug addObject:@"Registered nib names:"];
+        [debug addObject:[self.registeredNibNames description]];
+    }
+
+    if (self.registeredSupplementaryViewIdentifiers.count > 0) {
+        [debug addObject:@"Registered supplementary view identifiers:"];
+        [debug addObject:[self.registeredSupplementaryViewIdentifiers description]];
+    }
+
+    if (self.registeredSupplementaryViewNibNames.count > 0) {
+        [debug addObject:@"Registered supplementary view nib names:"];
+        [debug addObject:self.registeredSupplementaryViewNibNames];
+    }
+
+    if ([self.updater isKindOfClass:[IGListAdapterUpdater class]]) {
+        [debug addObject:[NSString stringWithFormat:@"IGListAdapterUpdater instance %p:", self.updater]];
+        [debug addObjectsFromArray:IGListDebugIndentedLines([(IGListAdapterUpdater *)self.updater debugDescriptionLines])];
+    }
+
+    [debug addObject:[NSString stringWithFormat:@"Section map details:"]];
+    [debug addObjectsFromArray:IGListDebugIndentedLines([self.sectionMap debugDescriptionLines])];
+
+    if (self.previousSectionMap != nil) {
+        [debug addObject:[NSString stringWithFormat:@"Previous section map details:"]];
+        [debug addObjectsFromArray:IGListDebugIndentedLines([self.previousSectionMap debugDescriptionLines])];
+    }
+
+    [debug addObject:[NSString stringWithFormat:@"Collection view details:"]];
+    [debug addObjectsFromArray:IGListDebugIndentedLines([self.collectionView debugDescriptionLines])];
+#endif // #if IGLK_DEBUG_DESCRIPTION_ENABLED
+    return debug;
+}
+
+@end
diff --git a/Source/Internal/IGListAdapterUpdater+DebugDescription.h b/Source/Internal/IGListAdapterUpdater+DebugDescription.h
new file mode 100644
index 00000000..07d0fcf6
--- /dev/null
+++ b/Source/Internal/IGListAdapterUpdater+DebugDescription.h
@@ -0,0 +1,16 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <IGListKit/IGListKit.h>
+
+@interface IGListAdapterUpdater (DebugDescription)
+
+- (NSArray<NSString *> *)debugDescriptionLines;
+
+@end
diff --git a/Source/Internal/IGListAdapterUpdater+DebugDescription.m b/Source/Internal/IGListAdapterUpdater+DebugDescription.m
new file mode 100644
index 00000000..22553d40
--- /dev/null
+++ b/Source/Internal/IGListAdapterUpdater+DebugDescription.m
@@ -0,0 +1,77 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "IGListAdapterUpdater+DebugDescription.h"
+
+#import "IGListAdapterUpdaterInternal.h"
+#import "IGListBatchUpdateData+DebugDescription.h"
+#import "IGListDebuggingUtilities.h"
+
+#if IGLK_DEBUG_DESCRIPTION_ENABLED
+static NSMutableArray *linesFromObjects(NSArray *objects) {
+    NSMutableArray *lines = [NSMutableArray new];
+    for (id object in objects) {
+        [lines addObject:[NSString stringWithFormat:@"Object %p of type %@ with identifier %@",
+                          object, NSStringFromClass([object class]), [object diffIdentifier]]];
+    }
+    return lines;
+}
+#endif // #if IGLK_DEBUG_DESCRIPTION_ENABLED
+
+@implementation IGListAdapterUpdater (DebugDescription)
+
+- (NSArray<NSString *> *)debugDescriptionLines {
+    NSMutableArray *debug = [NSMutableArray new];
+#if IGLK_DEBUG_DESCRIPTION_ENABLED
+    [debug addObject:[NSString stringWithFormat:@"Moves as deletes+inserts: %@", IGListDebugBOOL(self.movesAsDeletesInserts)]];
+    [debug addObject:[NSString stringWithFormat:@"Allows background reloading: %@", IGListDebugBOOL(self.allowsBackgroundReloading)]];
+    [debug addObject:[NSString stringWithFormat:@"Has queued reload data: %@", IGListDebugBOOL(self.hasQueuedReloadData)]];
+    [debug addObject:[NSString stringWithFormat:@"Queued update is animated: %@", IGListDebugBOOL(self.queuedUpdateIsAnimated)]];
+
+    NSString *stateString;
+    switch (self.state) {
+        case IGListBatchUpdateStateIdle:
+            stateString = @"Idle";
+            break;
+        case IGListBatchUpdateStateQueuedBatchUpdate:
+            stateString = @"Queued batch update";
+            break;
+        case IGListBatchUpdateStateExecutedBatchUpdateBlock:
+            stateString = @"Executed batch update block";
+            break;
+        case IGListBatchUpdateStateExecutingBatchUpdateBlock:
+            stateString = @"Executing batch update block";
+            break;
+    }
+    [debug addObject:[NSString stringWithFormat:@"State: %@", stateString]];
+
+    if (self.applyingUpdateData != nil) {
+        [debug addObject:@"Batch update data:"];
+        [debug addObjectsFromArray:IGListDebugIndentedLines([self.applyingUpdateData debugDescriptionLines])];
+    }
+
+    if (self.fromObjects != nil) {
+        [debug addObject:@"From objects:"];
+        [debug addObjectsFromArray:IGListDebugIndentedLines(linesFromObjects(self.fromObjects))];
+    }
+
+    if (self.toObjects != nil) {
+        [debug addObject:@"To objects:"];
+        [debug addObjectsFromArray:IGListDebugIndentedLines(linesFromObjects(self.toObjects))];
+    }
+
+    if (self.pendingTransitionToObjects != nil) {
+        [debug addObject:@"Pending objects:"];
+        [debug addObjectsFromArray:IGListDebugIndentedLines(linesFromObjects(self.pendingTransitionToObjects))];
+    }
+#endif // #if IGLK_DEBUG_DESCRIPTION_ENABLED
+    return debug;
+}
+
+@end
diff --git a/Source/Internal/IGListAdapterUpdaterInternal.h b/Source/Internal/IGListAdapterUpdaterInternal.h
index 9de37264..6295c1f0 100644
--- a/Source/Internal/IGListAdapterUpdaterInternal.h
+++ b/Source/Internal/IGListAdapterUpdaterInternal.h
@@ -41,6 +41,7 @@ FOUNDATION_EXTERN void convertReloadToDeleteInsert(NSMutableIndexSet *reloads,
 @property (nonatomic, assign, getter=hasQueuedReloadData) BOOL queuedReloadData;
 
 @property (nonatomic, assign) IGListBatchUpdateState state;
+@property (nonatomic, strong, nullable) IGListBatchUpdateData *applyingUpdateData;
 
 - (void)performReloadDataWithCollectionView:(UICollectionView *)collectionView;
 - (void)performBatchUpdatesWithCollectionView:(UICollectionView *)collectionView;
diff --git a/Source/Internal/IGListBatchUpdateData+DebugDescription.h b/Source/Internal/IGListBatchUpdateData+DebugDescription.h
new file mode 100644
index 00000000..a77072a9
--- /dev/null
+++ b/Source/Internal/IGListBatchUpdateData+DebugDescription.h
@@ -0,0 +1,16 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <IGListKit/IGListKit.h>
+
+@interface IGListBatchUpdateData (DebugDescription)
+
+- (NSArray<NSString *> *)debugDescriptionLines;
+
+@end
diff --git a/Source/Internal/IGListBatchUpdateData+DebugDescription.m b/Source/Internal/IGListBatchUpdateData+DebugDescription.m
new file mode 100644
index 00000000..bdf703cd
--- /dev/null
+++ b/Source/Internal/IGListBatchUpdateData+DebugDescription.m
@@ -0,0 +1,40 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "IGListBatchUpdateData+DebugDescription.h"
+
+@implementation IGListBatchUpdateData (DebugDescription)
+
+- (NSArray<NSString *> *)debugDescriptionLines {
+    NSMutableArray *debug = [NSMutableArray new];
+#if IGLK_DEBUG_DESCRIPTION_ENABLED
+    [debug addObject:[NSString stringWithFormat:@"Insert sections: %@", self.insertSections]];
+    [debug addObject:[NSString stringWithFormat:@"Delete sections: %@", self.deleteSections]];
+
+    for (IGListMoveIndex *move in self.moveSections) {
+        [debug addObject:[NSString stringWithFormat:@"Move from section %zi to %zi", move.from, move.to]];
+    }
+
+    for (NSIndexPath *path in self.deleteIndexPaths) {
+        [debug addObject:[NSString stringWithFormat:@"Delete section %zi item %zi", path.section, path.item]];
+    }
+
+    for (NSIndexPath *path in self.insertIndexPaths) {
+        [debug addObject:[NSString stringWithFormat:@"Insert section %zi item %zi", path.section, path.item]];
+    }
+
+    for (IGListMoveIndexPath *move in self.moveIndexPaths) {
+        [debug addObject:[NSString stringWithFormat:@"Move from section %zi item %zi to section %zi item %zi",
+         move.from.section, move.from.item, move.to.section, move.to.item]];
+    }
+#endif // #if IGLK_DEBUG_DESCRIPTION_ENABLED
+    return debug;
+}
+
+@end
diff --git a/Source/Internal/IGListDebugger.h b/Source/Internal/IGListDebugger.h
new file mode 100644
index 00000000..dcd2086e
--- /dev/null
+++ b/Source/Internal/IGListDebugger.h
@@ -0,0 +1,28 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <Foundation/Foundation.h>
+
+#import <IGListKit/IGListMacros.h>
+
+@class IGListAdapter;
+
+IGLK_SUBCLASSING_RESTRICTED
+@interface IGListDebugger : NSObject
+
++ (void)trackAdapter:(IGListAdapter *)adapter;
+
++ (NSArray<NSString *> *)adapterDescriptions;
+
++ (NSString *)dump;
+
+- (instancetype)init NS_UNAVAILABLE;
++ (instancetype)new NS_UNAVAILABLE;
+
+@end
diff --git a/Source/Internal/IGListDebugger.m b/Source/Internal/IGListDebugger.m
new file mode 100644
index 00000000..4368aff5
--- /dev/null
+++ b/Source/Internal/IGListDebugger.m
@@ -0,0 +1,40 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "IGListDebugger.h"
+
+#import "IGListDebuggingUtilities.h"
+#import "IGListAdapter+DebugDescription.h"
+
+@implementation IGListDebugger
+
+static NSHashTable<IGListAdapter *> *livingAdaptersTable = nil;
+
++ (void)trackAdapter:(IGListAdapter *)adapter {
+#if IGLK_DEBUG_DESCRIPTION_ENABLED
+    if (livingAdaptersTable == nil) {
+        livingAdaptersTable = [NSHashTable weakObjectsHashTable];
+    }
+    [livingAdaptersTable addObject:adapter];
+#endif // #if IGLK_DEBUG_DESCRIPTION_ENABLED
+}
+
++ (NSArray<NSString *> *)adapterDescriptions {
+    NSMutableArray *descriptions = [NSMutableArray new];
+    for (IGListAdapter *adapter in livingAdaptersTable) {
+        [descriptions addObject:[adapter debugDescription]];
+    }
+    return descriptions;
+}
+
++ (NSString *)dump {
+    return [[self adapterDescriptions] componentsJoinedByString:@"\n"];
+}
+
+@end
diff --git a/Source/Internal/IGListDebuggingUtilities.h b/Source/Internal/IGListDebuggingUtilities.h
new file mode 100644
index 00000000..96fce2ec
--- /dev/null
+++ b/Source/Internal/IGListDebuggingUtilities.h
@@ -0,0 +1,16 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <Foundation/Foundation.h>
+
+@class IGListAdapter;
+
+extern NSString *IGListDebugBOOL(BOOL b);
+
+extern NSArray<NSString *> *IGListDebugIndentedLines(NSArray<NSString *> *lines);
diff --git a/Source/Internal/IGListDebuggingUtilities.m b/Source/Internal/IGListDebuggingUtilities.m
new file mode 100644
index 00000000..764430c4
--- /dev/null
+++ b/Source/Internal/IGListDebuggingUtilities.m
@@ -0,0 +1,22 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "IGListDebuggingUtilities.h"
+
+NSString *IGListDebugBOOL(BOOL b) {
+    return b ? @"Yes" : @"No";
+}
+
+NSArray<NSString *> *IGListDebugIndentedLines(NSArray<NSString *> *lines) {
+    NSMutableArray *newLines = [NSMutableArray new];
+    for (NSString *line in lines) {
+        [newLines addObject:[NSString stringWithFormat:@"  %@", line]];
+    }
+    return newLines;
+}
diff --git a/Source/Internal/IGListSectionMap+DebugDescription.h b/Source/Internal/IGListSectionMap+DebugDescription.h
new file mode 100644
index 00000000..299b8fdc
--- /dev/null
+++ b/Source/Internal/IGListSectionMap+DebugDescription.h
@@ -0,0 +1,18 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <Foundation/Foundation.h>
+
+#import "IGListSectionMap.h"
+
+@interface IGListSectionMap (DebugDescription)
+
+- (NSArray<NSString *> *)debugDescriptionLines;
+
+@end
diff --git a/Source/Internal/IGListSectionMap+DebugDescription.m b/Source/Internal/IGListSectionMap+DebugDescription.m
new file mode 100644
index 00000000..54326d8c
--- /dev/null
+++ b/Source/Internal/IGListSectionMap+DebugDescription.m
@@ -0,0 +1,26 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "IGListSectionMap+DebugDescription.h"
+
+@implementation IGListSectionMap (DebugDescription)
+
+- (NSArray<NSString *> *)debugDescriptionLines {
+    NSMutableArray *debug = [NSMutableArray new];
+#if IGLK_DEBUG_DESCRIPTION_ENABLED
+    [self enumerateUsingBlock:^(id object, IGListSectionController *sectionController, NSInteger section, BOOL *stop) {
+        [debug addObject:[NSString stringWithFormat:@"Object and section controller at section: %zi:", section]];
+        [debug addObject:[NSString stringWithFormat:@"  %@", object]];
+        [debug addObject:[NSString stringWithFormat:@"  %@", sectionController]];
+    }];
+#endif // #if IGLK_DEBUG_DESCRIPTION_ENABLED
+    return debug;
+}
+
+@end
diff --git a/Source/Internal/UICollectionView+DebugDescription.h b/Source/Internal/UICollectionView+DebugDescription.h
new file mode 100644
index 00000000..d9b016de
--- /dev/null
+++ b/Source/Internal/UICollectionView+DebugDescription.h
@@ -0,0 +1,16 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <UIKit/UIKit.h>
+
+@interface UICollectionView (DebugDescription)
+
+- (NSArray<NSString *> *)debugDescriptionLines;
+
+@end
diff --git a/Source/Internal/UICollectionView+DebugDescription.m b/Source/Internal/UICollectionView+DebugDescription.m
new file mode 100644
index 00000000..26dde27d
--- /dev/null
+++ b/Source/Internal/UICollectionView+DebugDescription.m
@@ -0,0 +1,43 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "UICollectionView+DebugDescription.h"
+
+@implementation UICollectionView (DebugDescription)
+
+- (NSArray<NSString *> *)debugDescriptionLines; {
+    NSMutableArray *debug = [NSMutableArray new];
+#if IGLK_DEBUG_DESCRIPTION_ENABLED
+    [debug addObject:[NSString stringWithFormat:@"Class: %@, instance: %p", NSStringFromClass(self.class), self]];
+    [debug addObject:[NSString stringWithFormat:@"Data source: %@", self.dataSource]];
+    [debug addObject:[NSString stringWithFormat:@"Delegate: %@", self.delegate]];
+    [debug addObject:[NSString stringWithFormat:@"Layout: %@", self.collectionViewLayout]];
+    [debug addObject:[NSString stringWithFormat:@"Frame: %@, bounds: %@",
+                      NSStringFromCGRect(self.frame), NSStringFromCGRect(self.bounds)]];
+
+    const NSInteger sections = [self numberOfSections];
+    [debug addObject:[NSString stringWithFormat:@"Number of sections: %zi", sections]];
+
+    for (NSInteger section = 0; section < sections; section++) {
+        [debug addObject:[NSString stringWithFormat:@"  %zi items in section %zi",
+                          [self numberOfItemsInSection:section], section]];
+    }
+
+    [debug addObject:@"Visible cell details:"];
+    NSArray *visibleIndexPaths = [[self indexPathsForVisibleItems] sortedArrayUsingSelector:@selector(compare:)];
+    for (NSIndexPath *path in visibleIndexPaths) {
+        [debug addObject:[NSString stringWithFormat:@"  Visible cell at section %zi, item %zi:",
+         path.section, path.item]];
+        [debug addObject:[NSString stringWithFormat:@"  %@", [[self cellForItemAtIndexPath:path] description] ?: @""]];
+    }
+#endif // #if IGLK_DEBUG_DESCRIPTION_ENABLED
+    return debug;
+}
+
+@end
diff --git a/Tests/IGListDebuggerTests.m b/Tests/IGListDebuggerTests.m
new file mode 100644
index 00000000..695f0045
--- /dev/null
+++ b/Tests/IGListDebuggerTests.m
@@ -0,0 +1,51 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <XCTest/XCTest.h>
+
+#import <IGListKit/IGListKit.h>
+
+#import "IGListDebugger.h"
+#import "IGListAdapterUpdaterInternal.h"
+#import "IGListTestAdapterDataSource.h"
+#import "IGListMoveIndexInternal.h"
+#import "IGListMoveIndexPathInternal.h"
+
+@interface IGListDebuggerTests : XCTestCase
+
+@end
+
+@implementation IGListDebuggerTests
+
+- (void)test_whenSearchingAdapterInstances_thatCorrectCountReturned {
+    UIViewController *controller = [UIViewController new];
+    UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:CGRectZero collectionViewLayout:[UICollectionViewFlowLayout new]];
+    IGListAdapterUpdater *updater = [IGListAdapterUpdater new];
+    NSIndexPath *path = [NSIndexPath indexPathForItem:0 inSection:0];
+    updater.applyingUpdateData = [[IGListBatchUpdateData alloc] initWithInsertSections:[NSIndexSet indexSetWithIndex:1]
+                                                                        deleteSections:[NSIndexSet indexSetWithIndex:2]
+                                                                          moveSections:[NSSet setWithObject:[[IGListMoveIndex alloc] initWithFrom:3 to:4]]
+                                                                      insertIndexPaths:@[path]
+                                                                      deleteIndexPaths:@[path]
+                                                                        moveIndexPaths:@[[[IGListMoveIndexPath alloc] initWithFrom:path to:path]]];
+    IGListTestAdapterDataSource *dataSource = [IGListTestAdapterDataSource new];
+    dataSource.objects = @[@1, @2, @3];
+    IGListAdapter *adapter1 = [[IGListAdapter alloc] initWithUpdater:[IGListAdapterUpdater new] viewController:nil workingRangeSize:0];
+    adapter1.collectionView = collectionView;
+    adapter1.dataSource = dataSource;
+    IGListAdapter *adapter2 = [[IGListAdapter alloc] initWithUpdater:[IGListAdapterUpdater new] viewController:controller workingRangeSize:2];
+    adapter2.collectionView = collectionView;
+    IGListAdapter *adapter3 = [[IGListAdapter alloc] initWithUpdater:[IGListAdapterUpdater new] viewController:controller workingRangeSize:2];
+    adapter3.collectionView = collectionView;
+
+    NSArray *descriptions = [IGListDebugger adapterDescriptions];
+    XCTAssertEqual(descriptions.count, 3);
+}
+
+@end