The Human Experience is a comprehensive text that examines, analyzes and applies theories of humans, environments and human-environment interaction to professional thinking and action. Through the lens of their original theory, Explanatory Legitimacy, the authors differentiate descriptive from explanatory theories, and analyze the purposive, epistemological, and value base of theory in six major theoretical domains: longitudinal theories or those concerned with passages over time, environmental theories or those concerned with sets of conditions both interior and exterior to the body, categorical theories or those that parse populations into groups, systems theories which look at relationships among parts of wholes, and contemporary and emerging theories that advance pluralism as desirable and relevant to the 21st century. The authors highlight the previously unexamined values and assumptions that underlie theory, its generation and its use in professional practice and challenge the reader to answer two questions throughout the book: how do we know, and what do we do with our knowledge? Significant critical emphasis is devoted to diversity of humans and environments and the value-perimeter in which professionals create, analyze and use theory for decisions and activity.