Developmental science is an interdisciplinary scientific field dedicated to describing, understanding, and explaining change in behavior across the lifespan and the psychological, environmental, and biological processes that co-determine this change during the organism’s development. Developmental science is thus a broad discipline that lies at the intersection of psychology, biology, sociology, anthropology and other allied disciplines. Advancing Developmental Science: Philosophy, Theory, and Method reflects this broad view of developmental science, and reviews the philosophical, theoretical, and methodological issues facing the field. It does so within the Process-Relational paradigm, as described by developmentalist Willis Overton over the course of his career. Within that framework, this book explores development in a number of specific cognitive, neurobiological, and social domains, and provides students and researchers with a comprehensive suite of conceptual and methodological tools to describe, explain, and optimize intraindividual change across the lifespan.