This book provides a systematic literature review on flow theory, and its application into the development of the current empirical research on the identity experience. It opens up some new research questions at the frontiers of the field. The book offers an overview about the latest findings in flow research in relate to the aspects of identity such as personal identity, social identity and place identity. It integrates the latest knowledge on empirical studies of optimal experience with the theoretical foundation of psychological flow that was laid down in the last decades. The findings are relevant to any individual who wants to pursue a happy life.