The Critique of Regression presents the most in-depth critique of regression available in the psychoanalytic literature, whilst presenting the first psychoanalytic theory of irreversible lifespan development. The clinical implications are amply demonstrated in three chapter-length psychoanalytic cases. The most important implication is that when we revisit the past, in a private memory or in an analytic session, we remake it afresh in light of the present. The analysis of the past is always, in this sense, an exploration of the present. Gregory S. Rizzolo demonstrates that where we think we see returns, or regressions, to past stages of the lifespan, we in fact find the emergence of novel structures in subjective experience. Rizzolo considers the work of human development to be a work of mourning in which we lose, internalize and keep re-working the residue of a past to which we never return. The traditional notion of regression, which supports the fantasy of a literal return, operates as an intellectual defense against the mourning process. To critique the concept is to address the defense and to confront the loss of past relationships and of past versions of selfhood inherent in development. From the work of mourning emerge ever-new configurations of desire, defense and subjective meaning. The task of analysis is to cultivate, amidst the repetition of familiar patterns, the potential for novelty at play in each moment. This thought-provoking work will interest new and experienced psychoanalytic clinicians alike, who want to go beyond traditional theories of development to a contemporary look at how we develop inexorably across the lifespan.