The Second Sex caused uproar when it appeared in 1949. Simone de Beauvoir sets out groundbreaking ideas on what it meant to be a woman, charting the oppression of "the second sex." She argued that gender identity was shaped by upbringing in a world ruled by men, and her most startling thesis became a rallying cry for the feminist movement: "One is not born, but rather becomes, a woman." Decades on, Beauvoir's work is still the subject of intense debate—provoking anger and admiration in equal measure. It is impossible to consider the women's rights movement since World War II without talking about this landmark text.