The phrase "midlife crisis" today conjures up images of male indulgence and irresponsibility--an affluent, middle-aged man speeding off in a red sports car with a woman half his age--but before it became a gendered cliché, it gained traction as a feminist concept. In the 1970s, journalist Gail Sheehy used the term to describe a midlife period when both men and women might reassess their choices and seek a change in life. Sheehy's definition challenged the double standard of middle age--where aging is advantageous to men and detrimental to women--by viewing midlife as an opportunity rather than a crisis. Widely popular in the United States and internationally, the term was quickly appropriated by psychological and psychiatric experts and redefined as a male-centered, masculinist concept. The first book-length history of this controversial idea, Susanne Schmidt's Midlife Crisis recounts the surprising origin story of the midlife debate and traces its movement from popular culture into academia. Schmidt's engaging narrative of the feminist construction--and ensuing antifeminist backlash--of the midlife crisis illuminates a lost legacy of feminist thought, shedding important new light on the history of gender and American social science in the 1970s and beyond.