I just had a really irritating time tracking down bad memory access in ordered_index because I foolishly wrote something like this: typedef client_set::nth_index<0>::type address_index_type; address_index_type addressIndex = clients_.get<0>(); address_index_type::iterator iter = addressIndex.find(addr); The problem here is that I got my addressIndex by value in the second line. I may be overlooking something here, but I think it might be useful to make ordered_index noncopyable so that this would be detected at compile time instead of runtime. I nearly threw my monitor out the window over this one. Thanks, Dylan Trotter