M.J. Mulkay traces the development of certain recent versions of functionalism and exchange theory in sociology, with special attention to 'theoretical strategy'. He uses this term to refer to the policies which theorists adopt to ensure that their work contributes to their long range theoretical objectives. Such strategies are important, he believes, because they place limits on the theories with which they are associated. He shows how each of the theorists he studies devised a new strategy to replace the unsuccessful policies of a prior theory in a process of 'strategical dialectic'. This often has unforeseen consequences for the direction of theoretical growth, and the author interprets changes in theoretical perspective largely as products of these strategical innovations.