Personality theories based on factor analytic models have been criticized as inadequate because they describe the structure of traits without offering a good basis for predicting motivated behavior. Human Motivation and the Dynamic Calculus presents one of the few structured personality theories that directly address the problem of motivation. This update of the model Cattell developed in 1975 explains how goal directed behavior is predicted and reviews the many experimental studies which have been reported in the past nine years. The author points to a revolution in the field of applied psychology that makes structured personality-learning theory a useful approach in market research, advertising, and consumer behavior.