diff --git a/Foundation/CPKeyValueCoding.j b/Foundation/CPKeyValueCoding.j
index a4b02c50d..2169e9901 100644
--- a/Foundation/CPKeyValueCoding.j
+++ b/Foundation/CPKeyValueCoding.j
@@ -26,114 +26,91 @@
 @import "CPObject.j"
 
 
-var CPObjectAccessorsForClass   = nil,
-    CPObjectModifiersForClass   = nil;
-
 CPUndefinedKeyException     = @"CPUndefinedKeyException";
 CPTargetObjectUserInfoKey   = @"CPTargetObjectUserInfoKey";
 CPUnknownUserInfoKey        = @"CPUnknownUserInfoKey";
 
-var CPObjectAccessorsForClassKey = @"$CPObjectAccessorsForClassKey",
-    CPObjectModifiersForClassKey = @"$CPObjectModifiersForClassKey";
+var CPObjectAccessorsForClassKey            = @"$CPObjectAccessorsForClassKey",
+    CPObjectModifiersForClassKey            = @"$CPObjectModifiersForClassKey",
+    CPObjectInstanceVariablesForClassKey    = @"$CPObjectInstanceVariablesForClassKey";
 
-var Null = [CPNull null];
 var _accessorForKey = function(theClass, aKey)
 {
     var selector = nil,
         accessors = theClass[CPObjectAccessorsForClassKey];
 
-    if (accessors)
-    {
-        selector = accessors[aKey];
+    if (!accessors)
+        accessors = theClass[CPObjectAccessorsForClassKey] = { };
 
-        if (selector)
-            return selector === Null ? nil : selector;
-    }
-    else
-        accessors = theClass[CPObjectAccessorsForClassKey] = {};
+    else if (accessors.hasOwnProperty(aKey))
+        return accessors[aKey];
 
     var capitalizedKey = aKey.charAt(0).toUpperCase() + aKey.substr(1);
 
-    if ([theClass instancesRespondToSelector:selector = CPSelectorFromString("get" + capitalizedKey)] ||
-        [theClass instancesRespondToSelector:selector = CPSelectorFromString(aKey)] ||
-        [theClass instancesRespondToSelector:selector = CPSelectorFromString("is" + capitalizedKey)] ||
-        [theClass instancesRespondToSelector:selector = CPSelectorFromString("_get" + capitalizedKey)] ||   //FIXME: is deprecated in Cocoa 10.3
-        [theClass instancesRespondToSelector:selector = CPSelectorFromString("_" + aKey)] ||                //FIXME: is deprecated in Cocoa 10.3
-        [theClass instancesRespondToSelector:selector = CPSelectorFromString("_is" + capitalizedKey)])      //FIXME: was NEVER supported by Cocoa
-    {
-        accessors[aKey] = selector;
+    [theClass instancesRespondToSelector:selector = CPSelectorFromString("get" + capitalizedKey)] ||
+    [theClass instancesRespondToSelector:selector = CPSelectorFromString(aKey)] ||
+    [theClass instancesRespondToSelector:selector = CPSelectorFromString("is" + capitalizedKey)] ||
+    //FIXME: is deprecated in Cocoa 10.3
+    [theClass instancesRespondToSelector:selector = CPSelectorFromString("_get" + capitalizedKey)] ||
+    //FIXME: is deprecated in Cocoa 10.3
+    [theClass instancesRespondToSelector:selector = CPSelectorFromString("_" + aKey)] ||
+    //FIXME: was NEVER supported by Cocoa
+    [theClass instancesRespondToSelector:selector = CPSelectorFromString("_is" + capitalizedKey)] ||
+    (selector = nil);
 
-        return selector;
-    }
+    accessors[aKey] = selector;
 
-    accessors[aKey] = Null;
-
-    return nil;
+    return selector;
 }
 
 var _modifierForKey = function(theClass, aKey)
 {
-    if (!CPObjectModifiersForClass)
-        CPObjectModifiersForClass = [CPDictionary dictionary];
+    var selector = nil,
+        modifiers = theClass[CPObjectModifiersForClassKey];
 
-    var UID = [theClass UID],
-        selector = nil,
-        modifiers = [CPObjectModifiersForClass objectForKey:UID];
+    if (!modifiers)
+        modifiers = theClass[CPObjectModifiersForClassKey] = { };
 
-    if (modifiers)
-    {
-        selector = [modifiers objectForKey:aKey];
-
-        if (selector)
-            return selector === Null ? nil : selector;
-    }
-    else
-    {
-        modifiers = [CPDictionary dictionary];
-
-        [CPObjectModifiersForClass setObject:modifiers forKey:UID];
-    }
+    else if (modifiers.hasOwnProperty(aKey))
+        return modifiers[aKey];
 
     var capitalizedKey = aKey.charAt(0).toUpperCase() + aKey.substr(1) + ':';
 
-    if ([theClass instancesRespondToSelector:selector = CPSelectorFromString("set" + capitalizedKey)] ||
-        [theClass instancesRespondToSelector:selector = CPSelectorFromString("_set" + capitalizedKey)])     //FIXME: deprecated in Cocoa 10.3
-    {
-        [modifiers setObject:selector forKey:aKey];
+    [theClass instancesRespondToSelector:selector = CPSelectorFromString("set" + capitalizedKey)] ||
+    //FIXME: deprecated in Cocoa 10.3
+    [theClass instancesRespondToSelector:selector = CPSelectorFromString("_set" + capitalizedKey)] ||
+    (selector = nil);
 
-        return selector;
-    }
+    modifiers[aKey] = selector;
 
-    [modifiers setObject:Null forKey:aKey];
-
-    return nil;
+    return selector;
 }
 
-var _ivarForKey = function(theObject, aKey)
+var _ivarForKey = function(theClass, aKey)
 {
-    var ivar = '_' + aKey;
+    var variables = theClass[CPObjectInstanceVariablesForClassKey];
 
-    if (typeof theObject[ivar] != "undefined")
-        return ivar;
+    if (!variables)
+        variables = theClass[CPObjectInstanceVariablesForClassKey] = { };
 
-    var isKey = "is" + aKey.charAt(0).toUpperCase() + aKey.substr(1);
+    else if (variables.hasOwnProperty(aKey))
+        return variables[aKey];
 
-    ivar = '_' + isKey;
+    var name = '_' + aKey;
 
-    if (typeof theObject[ivar] != "undefined")
-        return ivar;
+    if (!class_getInstanceVariable(theClass, name))
+    {
+        var isKey = "is" + aKey.charAt(0).toUpperCase() + aKey.substr(1);
 
-    ivar = aKey;
+        class_getInstanceVariable(theClass, name = '_' + isKey) ||
+        class_getInstanceVariable(theClass, name = aKey) ||
+        class_getInstanceVariable(theClass, name = isKey) ||
+        (name = nil);
+    }
 
-    if (typeof theObject[ivar] != "undefined")
-        return ivar;
+    variables[aKey] = name;
 
-    ivar = isKey;
-
-    if (typeof theObject[ivar] != "undefined")
-        return ivar;
-
-    return nil;
+    return name;
 }
 
 @implementation CPObject (CPKeyValueCoding)
@@ -157,7 +134,7 @@ var _ivarForKey = function(theObject, aKey)
 
     if ([theClass accessInstanceVariablesDirectly])
     {
-        var ivar = _ivarForKey(self, aKey);
+        var ivar = _ivarForKey(theClass, aKey);
 
         if (ivar)
             return self[ivar];
@@ -170,7 +147,7 @@ var _ivarForKey = function(theObject, aKey)
 {
     var firstDotIndex = aKeyPath.indexOf(".");
 
-    if (firstDotIndex === -1)
+    if (firstDotIndex === CPNotFound)
         return [self valueForKey:aKeyPath];
 
     var firstKeyComponent = aKeyPath.substring(0, firstDotIndex),
@@ -193,6 +170,7 @@ var _ivarForKey = function(theObject, aKey)
 
         if (value === nil)
             [dictionary setObject:[CPNull null] forKey:key];
+
         else
             [dictionary setObject:value forKey:key];
     }
@@ -209,11 +187,12 @@ var _ivarForKey = function(theObject, aKey)
 
 - (void)setValue:(id)aValue forKeyPath:(CPString)aKeyPath
 {
-    if (!aKeyPath) aKeyPath = @"self";
+    if (!aKeyPath)
+        aKeyPath = @"self";
 
     var firstDotIndex = aKeyPath.indexOf(".");
 
-    if (firstDotIndex === -1)
+    if (firstDotIndex === CPNotFound)
         return [self setValue:aValue forKey:aKeyPath];
 
     var firstKeyComponent = aKeyPath.substring(0, firstDotIndex),
@@ -233,7 +212,7 @@ var _ivarForKey = function(theObject, aKey)
 
     if ([theClass accessInstanceVariablesDirectly])
     {
-        var ivar = _ivarForKey(self, aKey);
+        var ivar = _ivarForKey(theClass, aKey);
 
         if (ivar)
         {
@@ -259,8 +238,10 @@ var _ivarForKey = function(theObject, aKey)
     while (key = [keyEnumerator nextObject])
     {
         value = [keyedValues objectForKey: key];
+
         if (value === [CPNull null])
             [self setValue: nil forKey: key];
+
         else
             [self setValue: value forKey: key];
     }
@@ -275,7 +256,7 @@ var _ivarForKey = function(theObject, aKey)
 
 @end
 
-@implementation CPDictionary (KeyValueCoding)
+@implementation CPDictionary (CPKeyValueCoding)
 
 - (id)valueForKey:(CPString)aKey
 {
@@ -287,15 +268,16 @@ var _ivarForKey = function(theObject, aKey)
 
 - (void)setValue:(id)aValue forKey:(CPString)aKey
 {
-    if (aValue)
+    if (aValue !== nil)
         [self setObject:aValue forKey:aKey];
+
     else
-        [self removeObjectForKey: aKey];
+        [self removeObjectForKey:aKey];
 }
 
 @end
 
-@implementation CPNull (KeyValueCoding)
+@implementation CPNull (CPKeyValueCoding)
 
 - (id)valueForKey:(CPString)aKey
 {
diff --git a/Foundation/CPKeyValueObserving.j b/Foundation/CPKeyValueObserving.j
index 8fc5ca9ac..a83bf8bd5 100644
--- a/Foundation/CPKeyValueObserving.j
+++ b/Foundation/CPKeyValueObserving.j
@@ -37,19 +37,19 @@
 {
 }
 
-- (void)willChange:(CPKeyValueChange)change valuesAtIndexes:(CPIndexSet)indexes forKey:(CPString)key
+- (void)willChange:(CPKeyValueChange)aChange valuesAtIndexes:(CPIndexSet)indexes forKey:(CPString)aKey
 {
 }
 
-- (void)didChange:(CPKeyValueChange)change valuesAtIndexes:(CPIndexSet)indexes forKey:(CPString)key
+- (void)didChange:(CPKeyValueChange)aChange valuesAtIndexes:(CPIndexSet)indexes forKey:(CPString)aKey
 {
 }
 
-- (void)willChangeValueForKey:(CPString)key withSetMutation:(CPKeyValueSetMutationKind)mutationKind usingObjects:(CPSet)objects
+- (void)willChangeValueForKey:(CPString)aKey withSetMutation:(CPKeyValueSetMutationKind)aMutationKind usingObjects:(CPSet)objects
 {
 }
 
-- (void)didChangeValueForKey:(CPString)key withSetMutation:(CPKeyValueSetMutationKind)mutationKind usingObjects:(CPSet)objects
+- (void)didChangeValueForKey:(CPString)aKey withSetMutation:(CPKeyValueSetMutationKind)aMutationKind usingObjects:(CPSet)objects
 {
 }
 
@@ -282,18 +282,12 @@ var kvoNewAndOld = CPKeyValueObservingOptionNew | CPKeyValueObservingOptionOld,
     kvoClass._replacedKeys = _replacedKeys;
 
     //copy in the methods from our model subclass
-    var methodList = _CPKVOModelSubclass.method_list;
+    var methods = class_copyMethodList(_CPKVOModelSubclass);
+
     if ([_targetObject isKindOfClass:[CPDictionary class]])
-        methodList = methodList.concat(_CPKVOModelDictionarySubclass.method_list);
+        methods = methods.concat(class_copyMethodList(_CPKVOModelDictionarySubclass));
 
-    var count = methodList.length,
-        i = 0;
-
-    for (; i < count; i++)
-    {
-        var method = methodList[i];
-        class_addMethod(kvoClass, method_getName(method), method_getImplementation(method), "");
-    }
+    class_addMethods(kvoClass, methods);
 
     _targetObject.isa = kvoClass;
 }
diff --git a/Objective-J/Runtime.js b/Objective-J/Runtime.js
index 1da5c09f4..0d1145d0f 100644
--- a/Objective-J/Runtime.js
+++ b/Objective-J/Runtime.js
@@ -61,11 +61,12 @@ GLOBAL(objj_class) = function(displayName)
 
     this.name           = NULL;
     this.info           = 0;
-    this.ivars          = [];
+
+    this.ivar_list      = [];
+    this.ivar_store     = function() { };
+    this.ivar_dtable    = this.ivar_store.prototype;
 
     this.method_list    = [];
-    this.method_hash    = {};
-
     this.method_store   = function() { };
     this.method_dtable  = this.method_store.prototype;
 
@@ -135,10 +136,15 @@ GLOBAL(class_addIvar) = function(/*Class*/ aClass, /*String*/ aName, /*String*/
 {
     var thePrototype = aClass.allocator.prototype;
 
+    // FIXME: Use getInstanceVariable
     if (typeof thePrototype[aName] != "undefined")
         return NO;
 
-    aClass.ivars.push(new objj_ivar(aName, aType));
+    var ivar = new objj_ivar(aName, aType);
+
+    aClass.ivar_list.push(ivar);
+    aClass.ivar_dtable[aName] = ivar;
+
     thePrototype[aName] = NULL;
 
     return YES;
@@ -157,9 +163,12 @@ GLOBAL(class_addIvars) = function(/*Class*/ aClass, /*Array*/ivars)
         var ivar = ivars[index],
             name = ivar.name;
 
+        // FIXME: Use getInstanceVariable
         if (typeof thePrototype[name] === "undefined")
         {
-            aClass.ivars.push(ivar);
+            aClass.ivar_list.push(ivar);
+            aClass.ivar_dtable[name] = ivar;
+
             thePrototype[name] = NULL;
         }
     }
@@ -169,20 +178,18 @@ DISPLAY_NAME(class_addIvars);
 
 GLOBAL(class_copyIvarList) = function(/*Class*/ aClass)
 {
-    return aClass.ivars.slice(0);
+    return aClass.ivar_list.slice(0);
 }
 
 DISPLAY_NAME(class_copyIvarList);
 
-//#define class_copyIvarList(aClass) (aClass.ivars.slice(0))
+//#define class_copyIvarList(aClass) (aClass.ivar_list.slice(0))
 
 #define METHOD_DISPLAY_NAME(aClass, aMethod) (ISMETA(aClass) ? '+' : '-') + " [" + class_getName(aClass) + ' ' + method_getName(aMethod) + ']'
 
 GLOBAL(class_addMethod) = function(/*Class*/ aClass, /*SEL*/ aName, /*IMP*/ anImplementation, /*Array<String>*/ types)
 {
-    if (aClass.method_hash[aName])
-        return NO;
-
+    // FIXME: return NO if it exists?
     var method = new objj_method(aName, anImplementation, types);
 
     aClass.method_list.push(method);
@@ -215,9 +222,7 @@ GLOBAL(class_addMethods) = function(/*Class*/ aClass, /*Array*/ methods)
     {
         var method = methods[index];
 
-        if (aClass.method_hash[method.name])
-            continue;
-
+        // FIXME: Don't do it if it exists?
         method_list.push(method);
         method_dtable[method.name] = method;
 
@@ -246,6 +251,19 @@ GLOBAL(class_getInstanceMethod) = function(/*Class*/ aClass, /*SEL*/ aSelector)
 
 DISPLAY_NAME(class_getInstanceMethod);
 
+GLOBAL(class_getInstanceVariable) = function(/*Class*/ aClass, /*String*/ aName)
+{
+    if (!aClass || !aName)
+        return NULL;
+
+    // FIXME: this doesn't appropriately deal with Object's properties.
+    var variable = aClass.ivar_dtable[aName];
+
+    return variable;
+}
+
+DISPLAY_NAME(class_getInstanceVariable);
+
 GLOBAL(class_getClassMethod) = function(/*Class*/ aClass, /*SEL*/ aSelector)
 {
     if (!aClass || !aSelector)
@@ -370,12 +388,11 @@ GLOBAL(objj_allocateClassPair) = function(/*Class*/ superclass, /*String*/ aName
         // Give our current allocator all the instance variables of our super class' allocator.
         classObject.allocator.prototype = new superclass.allocator;
 
-        // "Inheret" parent methods.
-        classObject.method_store.prototype = new superclass.method_store;
-        classObject.method_dtable = classObject.method_store.prototype;
+        // "Inheret" parent properties.
+        classObject.ivar_dtable = classObject.ivar_store.prototype = new superclass.ivar_store;
+        classObject.method_dtable = classObject.method_store.prototype = new superclass.method_store;
 
-        metaClassObject.method_store.prototype = new superclass.isa.method_store;
-        metaClassObject.method_dtable = metaClassObject.method_store.prototype;
+        metaClassObject.method_dtable = metaClassObject.method_store.prototype = new superclass.isa.method_store;
 
         // Set up the actual class hierarchy.
         classObject.super_class = superclass;
@@ -456,7 +473,7 @@ class_createInstance = function(/*Class*/ aClass)
 
         while (theClass)
         {
-            var ivars = theClass.ivars,
+            var ivars = theClass.ivar_list,
                 count = ivars.length;
 
             while (count--)