Intended for courses on theories of human development, this new text presents nine theories grouped into three major families - those that emphasize biological systems; those that emphasize environmental factors; and those that emphasize a dynamic interaction between biological and environmental forces. The nine theories selected have a long and productive history in human development and continue to evolve as a result of new insights. The inclusion of social role theory and life course theory expand the book's relevance to the study of adulthood and aging. Grouping the theories by families enhances students' ability to think critically about theoretical ideas, assess the strengths and weaknesses of each theory, and gain a deeper understanding of how each theory guides research and application. The three families are introduced with a brief overview of the unique perspectives of each theory and the rationale for grouping these theories together. Discussion of each theory includes: the historical and cultural context in which the theory was developed; an overview of key concepts and important ideas; new directions in contemporary scientific work; a research example illustrating how the theory has been tested and modified; an application showing how the theory has guided the design of an intervention or program; an analysis of how the theory answers basic questions about human development; and a critique highlighting the theories' strengths and weaknesses. Theories of Human Development serves as a text in advanced undergraduate and/or beginning graduate courses in theories of human development. Its clear organization and engaging writing style make it accessible to students with a minimal background in human development.