Celebrating 50 years since its initial publication, Concepts and Theories of Human Development provides the most comprehensive overview of the foundational theoretical contributions to understanding human development, and the influence of these contributions on contemporary research and their application in developmental science. The book discusses the assumptions involved in such topics as the nature-nurture issue, the issue of continuity-discontinuity, dynamic, relational developmental systems (RDS)-based concepts and models, and the important role of philosophical ideas about theories—in particular, metatheories—in understanding the links between theory and research. Key features of this edition include:Two brand new chapters:“Developmental Methodology,” which explores the useful and problematic approaches to describing, explaining, and optimizing individual development across time and place offering insights into common pitfalls and how to avoid them“Applying Developmental Science,” which focuses on applying dynamic, RDS-based concepts to advance social justice, foster moral and character development, and strengthen democracy A new exploration of what it means to be human, a theme that is woven throughout the entire textDiscussions on recent methodological innovations in developmental science, providing tools to better understand the unique, person-specific features of human lifeAn essential resource for students and professionals alike, this book has become the go-to guide for graduate students studying for their comprehensive exams on human development. The book is supported by a website featuring videos from the author and scholars in the field of human development, available at routledgelearning.com/conceptshumandev.