Affect has always occupied a place of central importance in psychoanalysis, from Freud's early writings and revisions, to more recent contributions of many others, and into the current era of theoretical pluralism. Following Darwin and Freud, explored clinical and theoretical aspects of affect and motivation for over four decades; however, Tomkins' work is often misunderstood and rarely discussed comprehensively, particularly his more recent and posthumous elaborations. Tomkins is best viewed as presenting a developmental psychology of affect, and the theoretical and clinical aspects of Tomkins' work relevant to psychoanalysis are examined here with particular emphasis on his more recent revisions and additions. Tomkins and his colleagues described in detail the nature of affects and their triggering mechanisms; the development and transformations of the affect system; the potential for virtually unlimited ideo-affective structures resulting from this system; the relationships between affects, motivation, and other mental functions (e.g., drives and cognition); and various clinical implications.