This volume discusses the disparate perspectives on the construct and addresses the tendency to position purpose in the broader frame of positive psychology. It synthesizes distinct strands of research on purpose across the lifespan, it explores studies on the daily and longer-term experience of a purposeful existence, and it delves deeply into the wide range of measurement tools that have been used to assess the purpose construct. Further, it examines the prevalence and forms of purpose among diverse groups of youth and discusses the developmental trajectory of the construct.