David Gauthier's book represents the culmination of his work over the last twenty years on the theory of rational choice and on contractarian moral theory. It is the most important book on contractarianisni since Rawls‘ A Theory of Justice' and is mandatory reading for anyone specializing in contemporary moral theory. Gauthier does two distinct, although closely related, things in his book: (l) he defends a theory of rational choice, and (2) he defends a contractarian theory of morality. The two are related, since on his view moral principles are rational and impartial constraints on the pursuit of self—interest.