I can't seem to figure out if what I want is possible. I am using the Boost Serialization library to save the state of my program. I have a manager-type class which holds onto pointers of a base class. The Boost Serialization website has a lot to say about base and derived classes. In a tutorial they show one way to deal with them. But it assumes a priori knowledge of the derived classes: class bus_route { friend class boost::serialization::access; friend std::ostream & operator<<(std::ostream &os, const bus_route &br); typedef bus_stop * bus_stop_pointer; std::list stops; template<class Archive> void serialize(Archive &ar, const unsigned int version) { // in this program, these classes are never serialized directly but rather // through a pointer to the base class bus_stop. So we need a way to be // sure that the archive contains information about these derived classes. //ar.template register_type(); ar.register_type(static_cast(NULL)); // TYPES KNOWN A PRIORI //ar.template register_type(); ar.register_type(static_cast(NULL)); // TYPES KNOWN A PRIORI // serialization of stl collections is already defined // in the header ar & BOOST_SERIALIZATION_NVP(stops); } public: bus_route(){} void append(bus_stop *_bs) { stops.insert(stops.end(), _bs); } }; In my code, however, I don't know exactly what the derived classes might be. The derived objects are created and passed back to my manager class through the base pointer. One option I was considering was that when plugins register with the program, they would have to also register the derived class names with the archive. How this would actually be implemented, I have no idea. Can an archive object be created independently from the Serialization library, modified and then sent back to Serialization? Here is a simple test case I am working on, but I just can't get it to write out the derived classes to file: class base { friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int file_version) { ar & BOOST_SERIALIZATION_NVP(val); } public: base() : val(0.0) {} base(double b) : val(b) {} double val; }; class derived : public base { friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int file_version) { boost::serialization::void_cast_register(static_cast(NULL),static_cast(NULL)); ar & BOOST_SERIALIZATION_NVP(val); } public: derived() : base(0.0), val(0) {} derived(int a, double b) : base(b), val(a) {} int val; }; BOOST_CLASS_EXPORT_GUID(derived, "derived"); class manager { friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int file_version) { ar & BOOST_SERIALIZATION_NVP(objs); } public: std::list objs; }; void main() { manager mgr; // Creat some data to save derived *d1, *d2, *d3, *d4; d1 = new derived(1, 1.0); d2 = new derived(2, 3.0); mgr.objs.push_back( d1 ); mgr.objs.push_back( d2 ); { std::ofstream ofs("out.xml"); assert(ofs.good()); boost::archive::xml_oarchive oa(ofs); oa << BOOST_SERIALIZATION_NVP(mgr); ofs.close(); } manager new_mgr; { std::ifstream ifs("out.xml"); assert(ifs.good()); boost::archive::xml_iarchive ia(ifs); ia >> BOOST_SERIALIZATION_NVP(new_mgr); ifs.close(); } { std::ofstream ofs("check.xml"); assert(ofs.good()); boost::archive::xml_oarchive oa(ofs); oa << BOOST_SERIALIZATION_NVP(new_mgr); ofs.close(); } delete d1, d2; } I apologize if this commonly asked but I was just looking for some insight as to the best approach. J.D.