In what ways do individuals influence the course of their lives? How do people construct a unique life path within the opportunities and constraints afforded by their world? This volume examines how agency in the life course can be conceptualized and investigates the specific ways in which personal characteristics and contextual variables play a role in shaping individual lives. The contributors offer differing perspectives on agency, how its expression changes over a lifetime, and how it is constrained, channeled, or altered by cultural and social institutions. Each chapter focuses on one aspect of individual agency that can have a cumulative influence on an individual’s life. Following an overview of the subject by Lisa J. Crockett, Jochen Brandtstadter and Klaus Rothermund provide a life-span model of agency focused on intentional self-development and goal accommodation. Ellen Skinner and Kathleen Edge discuss the development of coping, a potential underpinning of agency. In a concluding essay, Michael J. Shanahan and Glen H. Elder Jr. examine agency within a life-course framework, showing that the impact of individual agency on people’s lives depends on the opportunities and constraints present during a particular historical era. Lisa J. Crockett is a professor of psychology at the University of Nebraska. She is the coeditor of Negotiating Adolescence in Times of Social Change and Pathways through Adolescence: Individual Development in Relation to Social Contexts.