AbstractThe emphasis in the social sciences has been on developing theory. The emphasis in OR has been on practice. It is argued in this paper that both traditions stand to gain much from close collaboration with each other. As a first step in this argument some highly relevant social science is introduced. As a second step, this is considered in relation to Beer's cybernetics and Checkland's soft systems methodology. These approaches demonstrate how subtle philosophical and sociological judgements can be incorporated in tools for practical action. At the same time, a much enhanced appreciation of the relative strengths of these methodologies is gained by viewing them from a social theory perspective. OR can help social scientists to make their findings usable in practice, and social science can help operational researchers achieve more sophisticated interventions and to learn from those interventions.