This paper summarises the arguments given in the IS research literature in favour of participation in IS development, and suggests that similar arguments can be made for the participation of all the stakeholders in IS research. It invites readers to consider how much involvement they "allow' stakeholders to have in their IS research. The paper concentrates on action research, and discusses the difficulties of evaluating action research and achieving authentic collaboration. It summarises the nature of "co-operative inquiry' and proposes that the research literature of cooperative inquiry can help us 1) to examine critically the extent of participation achieved in IS research and 2) to develop further and understand the nature of action research.