This article focuses on a particular kind of affect regulation, mentalized affectivity, which entails revaluing, not just modulating, affects. The author argues that affectivity challenges us to comprehend the impact of our representational world on affective experience and that this process plays a crucial role in psychoanalytic psychotherapy. Three elements of affectivity are delineated and divided into basic and complex forms: identifying affects (naming, distinguishing), processing affects (modulating, refining), and expressing affects (outwardly, inwardly/communicating). Case material is introduced to describe how affects manifest themselves clinically: The author distinguishes between what he terms strong and aporetic feelings, and he shows how affectivity works. Next he locates the concept of affectivity historically, emphasizing a debt to thinkers such as Jacobson, Loewald, Sandler, and Kernberg, who have sought to integrate ego psychology and object relations theory. Finally, he raises some general questions about affect regulation based on what he has proposed about affectivity.