Despite all the difficulties encountered in each incarnation of software reuse, we persist along the path of trying to figure out how we're going to create systems that meet the ever-increasing demand for capability and, with it, complexity and sheer size. Opportunistic software systems development is a reality today and for the foreseeable future, as the five articles in IEEE Software 's November/December 2008 special issue on OSSD demonstrate. This special issue aims to gather together insights into the viability, or perhaps the inevitability, of OSSD and to bring forward the most effective practices known today. Another goal is to point the way to what needs to be done to make OSSD more accessible to all practitioners. The editors hope to help the software community realize the importance of this new trend and the many aspects of it that have yet to be conquered.