According to "Installing Proto" at http://boost-sandbox.sourceforge.net/libs/proto/doc/html/boost_proto/users_g... " You can get Proto by downloading proto.zip from http://www.boost-consulting.com/vault/index.php?directory=Template%20Metapro... or by accessing Boost's SVN repository on SourceForge.net. Just go to http://svn.boost.org/trac/boost/wiki/BoostSubversion and follow the instructions there for anonymous SVN access. " The instructions linked to at http://svn.boost.org/trac/boost/wiki/BoostSubversion point to svn.boost.org (as I expected), where I can't find proto. So maybe it really does mean SourceForge; I thought that was defunct though. Giving the actual URL for the subversion tree would be really helpful... Oh hang, on I've found a _branch_ called proto at svn.boost.org; is that what I want?... except that it also doesn't seem to have a proto directory! Am I being an idiot? (I did get a bang on the head earlier, maybe it has given me a blind spot between property_tree and ptr_container...) Is everyone else using the zip file? Phil.