Joel, I hope you don't mind but I've just committed some relatively-trivial fixes to Fusion for two issues: The Boost.Config macro BOOST_PARTIAL_SPECIALIZATION_EXPLICT_ARGS has been renamed BOOST_NO_PARTIAL_SPECIALIZATION_IMPLICIT_DEFAULT_ARGS and docs and tests have been added now to Boost.Config. Includes of <utility> by fusion have been replaced by includes of <boost/config/no_tr1/utility.hpp> - this fixes some TR1 failures caused by cyclic dependencies between TR1 and Fusions Tuples. I'll be watching the test results over the next few days, but if there's anything you're not happy with I'll do some reverting :-) The changelog is here BTW: http://svn.boost.org/trac/boost/changeset?new=trunk%4044692&old=trunk%4044691 Cheers, John.