Index: src/OFObject+KeyValueCoding.m
==================================================================
--- src/OFObject+KeyValueCoding.m
+++ src/OFObject+KeyValueCoding.m
@@ -46,12 +46,37 @@
 {
 	SEL selector = sel_registerName([key UTF8String]);
 	const char *typeEncoding = [self typeEncodingForSelector: selector];
 	id ret;
 
-	if (typeEncoding == NULL)
-		return [self valueForUndefinedKey: key];
+	if (typeEncoding == NULL) {
+		size_t keyLength;
+		char *name;
+
+		if ((keyLength = [key UTF8StringLength]) < 1)
+			return [self valueForUndefinedKey: key];
+
+		if ((name = malloc(keyLength + 3)) == NULL)
+			@throw [OFOutOfMemoryException
+			    exceptionWithRequestedSize: keyLength + 3];
+
+		memcpy(name, "is", 2);
+		memcpy(name + 2, [key UTF8String], keyLength);
+		name[keyLength + 2] = '\0';
+
+		name[2] = toupper(name[2]);
+
+		selector = sel_registerName(name);
+
+		free(name);
+
+		typeEncoding = [self typeEncodingForSelector: selector];
+
+		if (typeEncoding == NULL ||
+		    *typeEncoding == '@' || *typeEncoding == '#')
+			return [self valueForUndefinedKey: key];
+	}
 
 	switch (nextType(&typeEncoding)) {
 	case '@':
 	case '#':
 		ret = [self performSelector: selector];

Index: tests/OFObjectTests.m
==================================================================
--- tests/OFObjectTests.m
+++ tests/OFObjectTests.m
@@ -54,11 +54,11 @@
 	double _doubleValue;
 }
 
 @property (retain) id objectValue;
 @property Class classValue;
-@property bool boolValue;
+@property (getter=isBoolValue) bool boolValue;
 @property char charValue;
 @property short shortValue;
 @property int intValue;
 @property long longValue;
 @property long long longLongValue;
@@ -240,11 +240,11 @@
 		   forKey: @"unsignedLongLongValue"]) &&
 	    R([m setValue: [OFNumber numberWithFloat: 110]
 		   forKey: @"floatValue"]) &&
 	    R([m setValue: [OFNumber numberWithDouble: 120]
 		   forKey: @"doubleValue"]) &&
-	    [m boolValue] == 0 &&
+	    [m isBoolValue] == 0 &&
 	    [m charValue] == 10 &&
 	    [m shortValue] == 20 &&
 	    [m intValue] == 30 &&
 	    [m longValue] == 40 &&
 	    [m longLongValue] == 50 &&