I got this working with a pretty direct copy/paste/find/replace using the current and.hpp as a template. See these links for the contents of my bitand.hpp and bitor.hpp: http://pastebin.com/f1afd8b3e http://pastebin.com/f47c85a29 It turns out that even though there is a not.hpp file, and ciso646 defines the macro 'not', it doesn't cause problems, at least for me. This might still cause issues down the road, maybe not. I'm not really sure what's going on in not.hpp. I don't know how this kind of thing works, but this seems like a legitimate (if obscure) problem in need of an official workaround. How do I go about getting this little fix uploaded to the boost repositories? Should I email the mpl maintainers directly, or do they read this list fairly often? Thanks, Erik Bryan -- View this message in context: http://old.nabble.com/Bug-using-mpl-with-%3Cciso646%3E-and-MSVC--tp26851153p... Sent from the Boost - Users mailing list archive at Nabble.com.