Boost.Bimap is ready for review. Here is the overview: With Boost.Bimap you can create associative containers in which both types can be used as key. A bimap<X,Y> can be thought of as a combination of a std::map<X,Y> and a std::map<Y,X>. The learning curve of bimap is almost flat if you know how to use standard containers. A great deal of effort has been put into mapping the naming scheme of the STL in Boost.Bimap. The library is designed to match the common STL containers. The project main page can be found here http://cablemodem.fibertel.com.ar/mcape/oss/projects/mc_projects/boost_proje... The sources have been upload to the Boost Vault too. http://boost-consulting.com/vault/index.php?direction=0&order=&directory=Containers& This library is the result of one of the ten Boost SoC projects. I was mentored by Joaquin López Muñoz, and he has been helping me to reach this point. (Thanks again!) An informal review was requested near the end of the SoC. The complete thread can be found here: http://archives.free.net.ph/message/20060809.053203.807d803b.en.html Changes since SoC dead-line: * New set_of type: unconstrained_set_of. Now it is possible to build standard unidirectional maps between the new framework. * Mutable data while iterating. In the case of non key-based set_of types (list_of, vector_of and unconstrained_set_of) the associated data of that side can be modified directly using iterators. * Internal reworking to simplify things. * More tests. * Proof-read docs. (Thanks Paul Giaccone!) Best regards Matias Capeletto