Offering a new and integrative approach to the study of formal models in the social and behavioral sciences, this book presents a theory forcing the specification of information currently neglected by game theory and offers a unified solution, or equilibrium, concept. Unifying the representation of social environments as situations, the theory extends the set of social environments included in current game theory, and accomodates coalition formation as well as bounded rationality concerning the perception and the computation abilities of the players. By applying the concept to game theory, the author relates many of the currently disparate solution concepts and suggests new and interesting ones.