This chapter reviews the development of post-war policy on the joint planning of health and social services for older people in the context of broader theoretical ideas about inter-organisational collaboration. It identifies the lack of organisational homogeneity and the absence of domain consensus across the health/social services boundary as the main obstacles to progress. The chapter suggests that, if these problems are to be properly understood, the broader policy context within which joint planning took place must also be investigated. It also suggests that central government’s attempts to encourage joint planning since the 1960s have repeatedly been hampered by distrust among local agencies of its more general policy intentions in this area. The chapter focuses on this most problematic area for joint working. It also reviews the development of post-war policy in this area and outline the main obstacles that have been identified as inhibitors of progress.