AbstractTo some kinds of social scientists and change agents, there is nothing new about the idea of working in multi-organizational fields. To others, however, exposure to such a field can be an unfamiliar, daunting and indeed often bewildering experience. This paper will argue that, despite some progress in recent years, there remains a paucity of well-grounded and well-articulated theory to guide the endeavours of researchers and change agents working between rather than within organizations. It will identify and review five contexts for learning in which relevant experiences have recently been accumulating: these are the contexts of exploratory social research, of implementation research, of community development, of organizational development and of operational research. It is suggested that the development of an appropriate theory calls for a drawing together of experiences and insights from those now working within these various contexts- and especially those who have opportunities to move between one context and another.