I've been corresponding privately with Robert for a while about the serialization library and he's encouraged me to start contributing to this forum. Recently I've been looking at using shared_ptr with the serialization tools as this is core to how I plan to use the library. We found that it was fine to serialize a shared_ptr<A> which held an A*. However, if there were a derived class B which was a public A then it wasn't possible to serialize a shared_ptr<A> which held a B* into an archive. The workaround for this, was to do this... BOOST_CLASS_EXPORT(boost::detail::sp_counted_base_impl< B*, boost::checked_deleter<B> >) That seems to give the library enough information to be able to serialize a shared_ptr<A> that holds a B*. To save typing I now use a macro HACK_SERIALIZATION_EXPORT_SHARED_POINTER(T) which is included in the attached file. Now let me introduce a new problem. I seem to have uncovered another bug. Using the workaround above I can demonstrate expected behaviour with text archives. However, if I try to serialize a shared_ptr<A> containing a B* to a BINARY archive then I get an assertion failure (puzzlingly in basic_text_oarchive.hpp - line 133). I don't have any problems serializing shared_ptr<A>s containing A*s to binary archives, and I don't have any problems at all with text archives. The file I've attached is a heavily modified version of demo_shared_ptr.cpp which performs four tests: 1. Serialize shared_ptr<A>s containing A*s to and from text archives. 2. Serialize shared_ptr<A>s containing B*s to and from text archives. 3. Serialize shared_ptr<A>s containing A*s to and from binary archives. 4. Serialize shared_ptr<A>s containing B*s to and from binary archives. Tests 1-3 all work fine. Test 4 fails as described. I'd appreciate it if others with an interest in the serialization library could take a look. I can quite believe that it's an error on my part but I haven't been able to spot it yet. DT