diff --git a/include/boost/python/object/class.hpp b/include/boost/python/object/class.hpp
index bc8f40d1..808e3669 100644
--- a/include/boost/python/object/class.hpp
+++ b/include/boost/python/object/class.hpp
@@ -6,16 +6,44 @@
 #ifndef CLASS_DWA20011214_HPP
 # define CLASS_DWA20011214_HPP
 
+# include <boost/python/module.hpp>
 # include <boost/python/detail/wrap_python.hpp>
 # include <boost/python/detail/config.hpp>
 # include <boost/utility.hpp>
 # include <boost/python/converter/type_id.hpp>
+# include <boost/python/reference.hpp>
 # include <boost/iterator_adaptors.hpp>
+# include <cstddef>
 
-namespace boost { namespace python { namespace objects { 
+namespace boost { namespace python {
+
+class module;
+
+namespace objects { 
 
 template <class T> struct holder;
 
+// To identify a class, we don't need cv/reference decorations
+typedef converter::undecorated_type_id_t class_id;
+
+struct BOOST_PYTHON_DECL class_base : noncopyable
+{
+    // constructor
+    class_base(
+        module& name_space              // Which name space the class will live in
+        , char const* name              // The name of the class
+        
+        , std::size_t num_types         // A list of class_ids. The first is the type
+        , class_id const*const types    // this is wrapping. The rest are the types of
+                                        // any bases.
+        );
+
+    // Retrieve a pointer to the underlying object
+    PyObject* object() const { return m_object.get(); }
+ private:
+    ref m_object;
+};
+
 // Base class for all holders
 struct BOOST_PYTHON_DECL instance_holder : noncopyable
 {
@@ -28,7 +56,7 @@ struct BOOST_PYTHON_DECL instance_holder : noncopyable
 
     virtual void* holds(converter::type_id_t) = 0;
 
-    void install(PyObject* inst);
+    void install(PyObject* inst) throw();
     
     struct iterator_policies : default_iterator_policies
     {
@@ -58,6 +86,8 @@ struct instance
     instance_holder* objects;
 };
 
+// Given a type_id, find the instance data which corresponds to it, or
+// return 0 in case no such type is held.
 BOOST_PYTHON_DECL void* find_instance_impl(PyObject*, converter::type_id_t);
 
 template <class T>
@@ -66,8 +96,8 @@ T* find_instance(PyObject* p, T* = 0)
     return static_cast<T*>(find_instance_impl(p, converter::type_id<T>()));
 }
 
-BOOST_PYTHON_DECL PyTypeObject* class_metatype();
-BOOST_PYTHON_DECL PyTypeObject* class_type();
+BOOST_PYTHON_DECL ref class_metatype();
+BOOST_PYTHON_DECL ref class_type();
 
 //
 // implementation
diff --git a/include/boost/python/object/class_unwrapper.hpp b/include/boost/python/object/class_unwrapper.hpp
index 666c6e93..0877ff24 100644
--- a/include/boost/python/object/class_unwrapper.hpp
+++ b/include/boost/python/object/class_unwrapper.hpp
@@ -18,14 +18,14 @@ struct class_unwrapper
     template <class Target>
     struct reference_unwrapper : converter::unwrapper<Target>
     {
-        bool convertible(PyObject* p) const
+        void* can_convert(PyObject* p) const
         {
-            return find_holder<T>(p) != 0;
+            return find_instance<T>(p);
         }
         
-        Target convert(PyObject* p, void*&) const
+        Target convert(PyObject* p, void* data, ) const
         {
-            return *find_holder<T>(p)->target();
+            return *find_instance<T>(p)->target();
         }
     };
     
diff --git a/include/boost/python/object/function.hpp b/include/boost/python/object/function.hpp
index ed7dd319..cc2695d8 100644
--- a/include/boost/python/object/function.hpp
+++ b/include/boost/python/object/function.hpp
@@ -22,10 +22,16 @@ struct BOOST_PYTHON_DECL function : PyObject
     ~function();
     
     PyObject* call(PyObject*, PyObject*) const;
-    void add_overload(function* overload);
+
+    // Add an attributeto the name_space with the given name. If it is
+    // a function object (this class), and an existing function is
+    // already there, add it as an overload.
+    static void add_to_namespace(
+        PyObject* name_space, char const* name, PyObject* attribute);
     
  private: // helper functions
     void argument_error(PyObject* args, PyObject* keywords) const;
+    void add_overload(function* overload);
     
  private: // data members
     py_function m_fn;
diff --git a/include/boost/python/object/value_holder.hpp b/include/boost/python/object/value_holder.hpp
index be7247da..d6e38a79 100644
--- a/include/boost/python/object/value_holder.hpp
+++ b/include/boost/python/object/value_holder.hpp
@@ -8,6 +8,8 @@
 
 # include <boost/python/object/class.hpp>
 # include <boost/python/converter/type_id.hpp>
+# include <boost/python/object/inheritance.hpp>
+# include <boost/ref.hpp>
 
 namespace boost { namespace python { namespace objects { 
 
@@ -76,9 +78,11 @@ struct value_holder_generator
 };
 
 template <class Held>
-void* value_holder<Held>::holds(converter::type_id_t x)
+void* value_holder<Held>::holds(converter::type_id_t dst_t)
 {
-    return x == converter::type_id<Held>() ? &m_held : 0;
+    converter::type_id_t src_t = converter::type_id<Held>();
+    return src_t == dst_t ? &m_held
+        : find_static_type(&m_held, src_t, dst_t);
 }
 
 }}} // namespace boost::python::objects
diff --git a/src/object/class.cpp b/src/object/class.cpp
index 8e85f38b..5ebabba1 100644
--- a/src/object/class.cpp
+++ b/src/object/class.cpp
@@ -6,8 +6,14 @@
 #include <boost/python/detail/config.hpp>
 #include <boost/python/detail/wrap_python.hpp>
 #include <boost/python/object/class.hpp>
+#include <boost/python/object/class_wrapper.hpp>
+#include <boost/python/objects.hpp>
+#include <boost/python/detail/map_entry.hpp>
+#include <boost/detail/binary_search.hpp>
 #include <boost/bind.hpp>
+#include <boost/python/detail/wrap_python.hpp>
 #include <functional>
+#include <vector>
 
 namespace boost { namespace python { namespace objects { 
 
@@ -64,6 +70,20 @@ PyTypeObject class_metatype_object = {
         // PyType_GenericNew                       /* tp_new */
 };
 
+// Get the metatype object for all extension classes.
+BOOST_PYTHON_DECL ref class_metatype()
+{
+    if (class_metatype_object.tp_dict == 0)
+    {
+        class_metatype_object.ob_type = &PyType_Type;
+        class_metatype_object.tp_base = &PyType_Type;
+        if (PyType_Ready(&class_metatype_object))
+            return ref();
+    }
+    return ref((PyObject*)&class_metatype_object, ref::increment_count);
+}
+
+// Do we really need this? I'm beginning to think we don't!
 PyTypeObject class_type_object = {
     PyObject_HEAD_INIT(0) //&class_metatype_object)
         0,
@@ -107,33 +127,21 @@ PyTypeObject class_type_object = {
         PyType_GenericNew
 };
 
-BOOST_PYTHON_DECL PyTypeObject* class_metatype()
-{
-    if (class_metatype_object.tp_dict == 0)
-    {
-        class_metatype_object.ob_type = &PyType_Type;
-        class_metatype_object.tp_base = &PyType_Type;
-        if (PyType_Ready(&class_metatype_object))
-            return 0;
-    }
-    Py_INCREF(&class_metatype_object);
-    return &class_metatype_object;
-}
-
-BOOST_PYTHON_DECL PyTypeObject* class_type()
+BOOST_PYTHON_DECL ref class_type()
 {
     if (class_type_object.tp_dict == 0)
     {
-        class_type_object.ob_type = class_metatype();
+        class_type_object.ob_type = (PyTypeObject*)class_metatype().release();
         class_type_object.tp_base = &PyBaseObject_Type;
         if (PyType_Ready(&class_type_object))
-            return 0;
+            return ref();
     }
-    Py_INCREF(&class_type_object);
-    return &class_type_object;
+    return ref((PyObject*)&class_type_object, ref::increment_count);
 }
 
-void instance_holder::install(PyObject* self)
+// Install the instance data for a C++ object into a Python instance
+// object.
+void instance_holder::install(PyObject* self) throw()
 {
     assert(self->ob_type->ob_type == &class_metatype_object);
     m_next = ((instance*)self)->objects;
@@ -157,4 +165,76 @@ find_instance_impl(PyObject* inst, converter::type_id_t type)
     return 0;
 }
 
+namespace
+{
+  struct class_registry
+  {
+   public:
+      ref get(class_id id) const;
+      void set(class_id, ref class_object);
+   private:
+      typedef detail::map_entry<class_id,ref> entry;
+      std::vector<entry> m_impl;
+  };
+
+  class_registry& registry()
+  {
+      static class_registry x;
+      return x;
+  }
+
+  ref class_registry::get(class_id id) const
+  {
+      std::vector<entry>::const_iterator start = m_impl.begin();
+      std::vector<entry>::const_iterator finish = m_impl.end();
+
+      std::vector<entry>::const_iterator p
+          = boost::detail::lower_bound(start, finish, id);
+      
+      if (p == finish && p->key != id)
+      {
+          string report("extension class wrapper for base class ");
+          (report += id.name()) += "has not been created yet";
+          PyErr_SetObject(PyExc_RuntimeError, report.get());
+          throw error_already_set();
+      }
+      return p->value;
+  }
+
+  void class_registry::set(class_id id, ref object)
+  {
+      std::vector<entry>::iterator start = m_impl.begin();
+      std::vector<entry>::iterator finish = m_impl.end();
+      m_impl.insert(
+          boost::detail::lower_bound(start, finish, id)
+          , entry(id, object));
+  }
+}
+
+class_base::class_base(
+    module& m, char const* name, std::size_t num_types, class_id const* const types)
+{
+    class_registry& r = registry();
+    assert(num_types >= 1);
+    tuple bases(std::max(num_types - 1, static_cast<std::size_t>(1)));
+    if (num_types > 1)
+    {
+        for (std::size_t i = 1; i < num_types; ++i)
+            bases.set_item(i - 1, r.get(types[i]));
+    }
+    else
+    {
+        bases.set_item(0, class_type());
+    }
+    
+    tuple args(3);
+    args.set_item(0, string(name).reference());
+    args.set_item(1, bases.reference());
+    args.set_item(2, dictionary().reference());
+    
+    m_object = ref(PyObject_CallObject(class_metatype().get(), args.get()));
+    r.set(types[0], m_object);
+    m.add(m_object, name);
+}
+
 }}} // namespace boost::python::objects