John Roberts is a professor of aesthetics, well-read in a variety of disciplines, and a seasoned Hegelian. In his examination of the necessity of errors, he explores the role and functioning of mistakes in diverse fields such as the practice of revolutionary movements, epistemology, and psychoanalysis, viewing them as quasi-Freudian slips of the historical process. Roberts makes it clear why 20th-century theorists could come to the conclusion that Hegel's Phenomenology of Spirit is a hilariously funny book: Hegel and Roberts, following in his footsteps, gently but firmly undermine the ground beneath the feet of the self-assured and sovereignty-convinced subject of the dialectically enlightened world. The author understands those who make mistakes as thinking within historically determined horizons of truth.