Social psychology remains unbalanced as long as we study human behaviour exclusively 'from the outside', leaving out of account people's own reasons for acting as they do. Originally published in 1982, the result of the author's emphasis on the cognitive dimension is a much more complete and well-rounded textbook of social psychology than had previously been available. Beginning with an exploration of the various models that have been suggested to explain the whole range of social behaviour, the book goes on to argue that consistency – comparability, similarity, congruity – is the principle by which social behaviour can best be explained. It goes into the cognitive processes that determine social attitudes, ascription of certain characteristics to individuals, and the attraction we feel to some people but not others. It also shows how these processes can be extended and affected by group membership.

Consistency is important, the author believes, because it allows the maximum prediction of others' behaviour and guidance of our own. These functions are demonstrated by observing failures of consistency, such as occur in humour and in negative self-esteem, and the author examines these inconsistencies in a final chapter.