Action research has been described as the basic model — underlying most organisation development activities. It is, however, a process which is not too well understood but which apparently offers some promise of effectively applying behavioural science findings to organisational problems whilst at the same time adding to social science knowledge. In this article the history and development of action research is considered; action research is then defined by contrasting and comparing it with pure and applied research and consultancy; finally through an examination of some cases its advantages and limitations in practice are explored.