This chapter examines the scope of the field of lifelong learning, covering definitions, environmental pressures, principal theories of development and learning, and environmental resources and structures that support lifelong learning. Lifelong learning is a dynamic process that varies depending on individual skills and motivation for self-regulated, generative learning and life events that impose challenges that sometimes demand incremental/adaptive change and at other times require frame-breaking change and transformational learning. This can occur at any stage of life and can be related to career and nonwork experiences and goals. The chapter previews the major sections of this handbook, including theoretical perspectives, organizational programs and support for lifelong learning, learning technologies, international perspectives, emerging issues and challenges, and future perspectives.