The evolution of massive binaries in a dense stellar cluster environment

Massive stars are among the most important objects in the Universe and many (most?) of them are formed in binaries. A selection of observational and theoretical facts that illustrate the importance of binaries and the evolution of massive and very massive stars in clusters with special emphasis on massive binaries have been summarized in two recent review papers (Vanbeveren, 2009, 2010). The present paper can be considered as an addendum of both reviews.