This is the new edition of Motivation and Action. The first English edition, based on the second German edition and published by Springer-Verlag in 1991, was written by Heinz Heckhausen, who died on October 30, 1988. Springer-Verlag and I agreed that a revised edition of this influential textbook on motivational psychology was needed, and Cambridge University Press was ready to publish the international edition of the new book. The edition written by Heinz Heckhausen was already over 15 years old, and it was clear that considerable revisions would be required. Enormous progress has since been made in motivation psychology and its subdomains. There have been major conceptual and empirical innovations, informed and inspired in part by the research perspectives highlighted by Heinz Heckhausen (especially in Chapter 6, “Achievement Motivation,” and Chapter 15, “Motivation and Development”), as well as by the study of implicit versus explicit motives, and by the lifespan theory of control. It would be a Herculean task to provide a comprehensive overview of all these developments and to survey the field of motivation psychology in its full range and complexity. No single scientist could now hope to follow in Heinz Heckhausen's footsteps and accomplish this task alone. A collaborative approach was clearly called for, and a look at the ranks of Heinz Heckhausen's students and their students shows that almost every subdomain of motivation psychology is represented by one or several renowned researchers.