diff --git a/osx/BoE.xcodeproj/project.pbxproj b/osx/BoE.xcodeproj/project.pbxproj
index cfa08db0..9e70bfa0 100644
--- a/osx/BoE.xcodeproj/project.pbxproj
+++ b/osx/BoE.xcodeproj/project.pbxproj
@@ -43,6 +43,7 @@
 		2BF04B2E0BF51924006C0831 /* boe.town.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 2BF04B090BF51924006C0831 /* boe.town.cpp */; };
 		2BF04DE90BF7A6FE006C0831 /* Carbon.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 2BF04DE80BF7A6FE006C0831 /* Carbon.framework */; };
 		9122832E0FCF6C7200B21642 /* busywork.exs in CopyFiles */ = {isa = PBXBuildFile; fileRef = 9122832D0FCF6C7200B21642 /* busywork.exs */; };
+		912283C90FD0E16C00B21642 /* undo.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 912283C80FD0E16C00B21642 /* undo.cpp */; };
 		9127903E0F9B7F49007B0D52 /* boe.actions.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 2BF04ACF0BF51923006C0831 /* boe.actions.cpp */; };
 		9127903F0F9B7F50007B0D52 /* boe.graphics.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 2BF04AD30BF51923006C0831 /* boe.graphics.cpp */; };
 		912793640F9C107B007B0D52 /* viewdlog.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 91B3EEF80F969BA700BF5B67 /* viewdlog.cpp */; };
@@ -331,6 +332,8 @@
 		910BBAD90FB91D2A001E34EA /* dlogutil.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = dlogutil.h; path = dialogxml/dlogutil.h; sourceTree = "<group>"; };
 		910BBADA0FB91D2A001E34EA /* dlogutil.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = dlogutil.cpp; path = dialogxml/dlogutil.cpp; sourceTree = "<group>"; };
 		9122832D0FCF6C7200B21642 /* busywork.exs */ = {isa = PBXFileReference; lastKnownFileType = file; path = busywork.exs; sourceTree = "<group>"; };
+		912283C70FD0E16B00B21642 /* undo.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = undo.h; path = tools/undo.h; sourceTree = "<group>"; };
+		912283C80FD0E16C00B21642 /* undo.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = undo.cpp; path = tools/undo.cpp; sourceTree = "<group>"; };
 		912793480F9C0FE6007B0D52 /* ViewDlog.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = ViewDlog.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		912798AE0F9CA636007B0D52 /* dlgbtns.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = dlgbtns.cpp; path = tools/dlgbtns.cpp; sourceTree = "<group>"; };
 		91279BAD0F9CFCBA007B0D52 /* boescenario.icns */ = {isa = PBXFileReference; lastKnownFileType = image.icns; path = boescenario.icns; sourceTree = "<group>"; };
@@ -804,6 +807,8 @@
 				910BBA130FB8BE66001E34EA /* dialogs */,
 				913D03350FA1000200184C18 /* headers */,
 				913D03340FA0FFFF00184C18 /* src */,
+				912283C70FD0E16B00B21642 /* undo.h */,
+				912283C80FD0E16C00B21642 /* undo.cpp */,
 			);
 			name = tools;
 			sourceTree = "<group>";
@@ -1231,6 +1236,7 @@
 				91C1FCA90FCB6F7200EBAA65 /* field.cpp in Sources */,
 				91C1FCAA0FCB6F7200EBAA65 /* message.cpp in Sources */,
 				91C1FCAB0FCB6F7300EBAA65 /* pict.cpp in Sources */,
+				912283C90FD0E16C00B21642 /* undo.cpp in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/osx/tools/undo.cpp b/osx/tools/undo.cpp
new file mode 100644
index 00000000..73222ad1
--- /dev/null
+++ b/osx/tools/undo.cpp
@@ -0,0 +1,40 @@
+/*
+ *  undo.cpp
+ *  BoE
+ *
+ *  Created by Celtic Minstrel on 29/05/09.
+ *
+ */
+
+#include "undo.h"
+
+cUndoList::cUndoList(){
+	lastSave = cur = theList.begin();
+}
+
+size_t cUndoList::maxUndoSize = 0;
+
+//TODO: These functions should have error checking to ensure they do not access an out of bounds action
+void cUndoList::undo(){
+	(*cur)->undo();
+	cur--;
+}
+
+void cUndoList::redo(){
+	cur++;
+	(*cur)->redo();
+}
+
+void cUndoList::save(){
+	lastSave = cur;
+}
+
+void cUndoList::revert(){
+	while(cur != lastSave) undo();
+}
+
+void cUndoList::add(cAction* what){
+	theList.push_back(what);
+	num_actions++;
+	while(num_actions > maxUndoSize) theList.pop_front(), num_actions--;
+}
diff --git a/osx/tools/undo.h b/osx/tools/undo.h
new file mode 100644
index 00000000..bc205c1e
--- /dev/null
+++ b/osx/tools/undo.h
@@ -0,0 +1,45 @@
+/*
+ *  undo.h
+ *  BoE
+ *
+ *  Created by Celtic Minstrel on 29/05/09.
+ *
+ *  For use in creating an undo history in the scenario editor.
+ *  Could also be used in the PC editor.
+ *
+ */
+
+#include <list>
+
+class cAction {
+public:
+	virtual void undo() = 0; // undoes this action if it has not already been undone
+	virtual void redo() = 0; // redoes this action if it has been undone
+	virtual bool isDone() = 0; // checks to see whether the action has been undone; returns false if it has
+	virtual std::string getActionName() = 0; // returns the name of this action for display in the Edit menu
+	virtual ~cAction();
+};
+
+class cUndoList {
+	std::list<cAction*> theList;
+	std::list<cAction*>::iterator cur, lastSave;
+	size_t num_actions;
+public:
+	cUndoList();
+	void undo(); // undoes the current action and decrements the cur pointer
+	void redo(); // increments the cur pointer and redoes the current action
+	void save(); // sets the last saved action to the current action
+	void revert(); // undoes all actions back to (but excluding) the last saved action
+	void add(cAction* what);
+	static size_t maxUndoSize;
+};
+
+// As a special convention, I will prefix action classes with 'a' instead of 'c'
+/*
+class aEditMonster : public cAction {
+	cMonster oldMonst, newMonst;
+};
+
+class aEditItem : public cAction {
+	cItemRec oldItem, newItem;
+};*/