diff --git a/base.rs b/base.rs
index 72fc9e1..55c09bc 100644
--- a/base.rs
+++ b/base.rs
@@ -10,17 +10,39 @@ pub type CFAllocatorRef = *__CFAllocator;
 struct __CFType { private: () }
 pub type CFTypeRef = *__CFType;
 
-trait CFType {
-    pure fn get(&self) -> CFTypeRef;
+struct CFType {
+    obj: CFTypeRef,
+
+    drop {
+        unsafe {
+            CFRelease(self.obj)
+        }
+    }
+}
+
+impl CFType : AbstractCFType {
+    pure fn as_type_ref(&self) -> CFTypeRef {
+        self.obj
+    }
+}
+
+trait AbstractCFType {
+    pure fn as_type_ref(&self) -> CFTypeRef;
 }
 
 trait CFTypeOps {
+    fn as_type(self) -> CFType;
     fn show(&self);
 }
 
-impl<T:CFType> T : CFTypeOps {
+impl<T:AbstractCFType> T : CFTypeOps {
+    // Consumes self.
+    fn as_type(self) -> CFType {
+        CFType { obj: self.as_type_ref() }
+    }
+
     fn show(&self) {
-        CFShow(self.get());
+        CFShow(self.as_type_ref());
     }
 }
 
diff --git a/boolean.rs b/boolean.rs
new file mode 100644
index 0000000..1febd7c
--- /dev/null
+++ b/boolean.rs
@@ -0,0 +1,53 @@
+use base::{AbstractCFType, CFRelease, CFRetain, CFTypeRef};
+use unsafe::reinterpret_cast;
+
+struct __CFBoolean { private: () }
+pub type CFBooleanRef = *__CFBoolean;
+
+struct CFBoolean {
+    obj: CFBooleanRef,
+
+    drop {
+        unsafe {
+            CFRelease(reinterpret_cast(self.obj));
+        }
+    }
+}
+
+mod CFBoolean {
+    fn wrap(obj: CFBooleanRef) -> CFBoolean {
+        CFBoolean { obj: obj }
+    }
+
+    fn true_value() -> CFBoolean {
+        unsafe {
+            let obj = kCFBooleanTrue;
+            CFRetain(reinterpret_cast(obj));
+            return wrap(obj);
+        }
+    }
+
+    fn false_value() -> CFBoolean {
+        unsafe {
+            let obj = kCFBooleanFalse;
+            CFRetain(reinterpret_cast(obj));
+            return wrap(obj);
+        }
+    }
+}
+
+impl CFBoolean : AbstractCFType {
+    pure fn as_type_ref(&self) -> CFTypeRef {
+        unsafe {
+            reinterpret_cast(self.obj)
+        }
+    }
+}
+
+#[link_args="-framework CoreFoundation"]
+#[nolink]
+extern {
+    const kCFBooleanTrue: CFBooleanRef;
+    const kCFBooleanFalse: CFBooleanRef;
+}
+
diff --git a/core_foundation.rc b/core_foundation.rc
index 1a172a7..7b0ee0c 100644
--- a/core_foundation.rc
+++ b/core_foundation.rc
@@ -1,4 +1,5 @@
 mod base;
+mod boolean;
 mod dictionary;
 mod string;
 mod test;
diff --git a/dictionary.rs b/dictionary.rs
index 0f99a95..b5235be 100644
--- a/dictionary.rs
+++ b/dictionary.rs
@@ -1,4 +1,4 @@
-use base::{CFAllocatorRef, CFIndex, CFRelease, CFType, CFTypeRef, kCFAllocatorDefault};
+use base::{AbstractCFType, CFAllocatorRef, CFIndex, CFRelease, CFTypeRef, kCFAllocatorDefault};
 use dvec::DVec;
 use libc::c_void;
 use ptr::to_unsafe_ptr;
@@ -31,7 +31,7 @@ pub struct CFDictionaryValueCallBacks {
 struct __CFDictionary { private: () }
 pub type CFDictionaryRef = *__CFDictionary;
 
-struct CFDictionary<K:CFType,V:CFType> {
+struct CFDictionary<K:AbstractCFType,V:AbstractCFType> {
     obj: CFDictionaryRef,
 
     drop {
@@ -42,18 +42,18 @@ struct CFDictionary<K:CFType,V:CFType> {
 }
 
 mod CFDictionary {
-    fn wrap<K:CFType,V:CFType>(obj: CFDictionaryRef) -> CFDictionary<K,V> {
+    fn wrap<K:AbstractCFType,V:AbstractCFType>(obj: CFDictionaryRef) -> CFDictionary<K,V> {
         CFDictionary { obj: obj }
     }
 
-    fn new_dictionary<K:CFType,V:CFType>(pairs: &[(K,V)]) -> CFDictionary<K,V> {
+    fn new_dictionary<K:AbstractCFType,V:AbstractCFType>(pairs: &[(K,V)]) -> CFDictionary<K,V> {
         let (keys, values) = (DVec(), DVec());
         for pairs.each |pair| {
             // FIXME: "let" would be much nicer here, but that doesn't work yet.
             match pair {
                 (ref key, ref value) => {
-                    keys.push(key.get());
-                    values.push(value.get());
+                    keys.push(key.as_type_ref());
+                    values.push(value.as_type_ref());
                 }
             }
         }
@@ -76,8 +76,8 @@ mod CFDictionary {
     }
 }
 
-impl<K:CFType,V:CFType> CFDictionary<K,V> : CFType {
-    pure fn get(&self) -> CFTypeRef {
+impl<K:AbstractCFType,V:AbstractCFType> CFDictionary<K,V> : AbstractCFType {
+    pure fn as_type_ref(&self) -> CFTypeRef {
         unsafe {
             reinterpret_cast(self.obj)
         }
diff --git a/string.rs b/string.rs
index 8f4069b..ad34e2b 100644
--- a/string.rs
+++ b/string.rs
@@ -1,5 +1,5 @@
-use base::{Boolean, CFAllocatorRef, CFIndex, CFRelease, CFType, CFTypeRef, kCFAllocatorDefault};
-use base::{kCFAllocatorNull};
+use base::{AbstractCFType, Boolean, CFAllocatorRef, CFIndex, CFRelease, CFTypeRef};
+use base::{kCFAllocatorDefault, kCFAllocatorNull};
 use libc::c_char;
 use unsafe::reinterpret_cast;
 
@@ -40,8 +40,8 @@ mod CFString {
     }
 }
 
-impl CFString : CFType {
-    pure fn get(&self) -> CFTypeRef {
+impl CFString : AbstractCFType {
+    pure fn as_type_ref(&self) -> CFTypeRef {
         unsafe {
             reinterpret_cast(self.obj)
         }
diff --git a/test.rs b/test.rs
index 71d13a9..edd2a5e 100644
--- a/test.rs
+++ b/test.rs
@@ -1,11 +1,12 @@
 use base::CFTypeOps;
+use boolean::CFBoolean;
 use dictionary::CFDictionary;
 use string::CFString;
 
 fn main() {
     let d = CFDictionary::new_dictionary([
-        (CFString::new_static("Foo"), CFString::new_static("Bar")),
-        (CFString::new_static("Baz"), CFString::new_static("Boo"))
+        (CFString::new_static("Foo"), CFString::new_static("Bar").as_type()),
+        (CFString::new_static("Baz"), CFBoolean::true_value().as_type())
     ]);
     (&d).show();
 }