Hi, Is it possible to enable serialization solely for a heirarchy of objects? I was thinking something like: template<typename Derived> struct implementation_level<Derived, typename ::boost::enable_if<::boost::is_base_of<Base,Derived> >::type> { typedef mpl::integral_c_tag tag; typedef mpl::int_< ::boost::serialization::object_serializable > type; BOOST_STATIC_CONSTANT(int,value = implementation_level::type::value ); }; But that requires implementation_level to be patched. Maybe there is another obvious way that I am missing. Thanks, Sohail