Shulamith Firestone’s theories were fierce and brilliantly argued but so radical it was easy to dismiss them as simply crazy; she believed that nothing less than total abolition of everything that makes men and women different, including childbearing and the nuclear family structure, will suffice to end sexual inequality. Firestone synthesized the theoretical frameworks of Marxist and psychoanalytic theory and was the first to apply them to feminism; no one before or since has articulated the problems of women as a social class so clearly. Though her positions still seem extreme, her idea of a future where gender has no cultural significance resonates more strongly now than ever. Plus, she’s funny: profane and clever and clear. Among world-changing thinkers, she’s the only one whose book I’d bring on a long bus ride.