This piece summarizes the argument of a key theoretical book of the late seventies, The Mermaid and the Minotaur, and includes a brief intellectual biography of its author, Dorothy Dinnerstein, whose work as a feminist psychologist took off from Freud, Ruth Benedict, Melanie Klein, Wolfgang Kohler, Norman O. Brown, and Solomon Asch. Mermaid describes a “malaise” in “human sexual arrangements,” divisions of labor and values between the sexes, which were once useful adaptations but are now destructive and limiting to all projects for human freedom, growth, and survival. Dinnerstein offers subtle analyses of the daily workings of sexism, the often small and usually unremarked betrayals of women’s aspirations for freedom. The Mermaid and the Minotaur deepens feminist understandings of how the oppression of women works, the common mechanisms that ensure that both men and women remain only half-adult, only half able to face current dangers to life on earth.