This book provides an innovative foundation for looking at human and social behavior u as a system of purposeful (teleological) events. It uses a systems theoretical approach for the study of these phenomena, and illustrates and extends general systems theory. Part One develops the concepts of traditional mechanism from which, successively, the concepts of "function," "choice," "goal-seeking," and "purposefulness" are derived, leading to a quantitative formulation of "personality". Part Two provides an analysis of aspects of purposeful behavior and personality, and Part Three explores the interaction of purposeful systems. Part Four is concerned with the study of social groups and ideal-seeking behavior. Finally, structural concepts underpinning the theoretical system are redefined in technological terms, thus demonstrating the non-vicious circularity and interdependence of all scientific concepts.