French writer, philosopher and activist Simone de Beauvoir was BOTD in 1908. Born in Paris to an impoverished bourgeois family, she studied philosophy at the École Normal Supérieure, where she met Jean-Paul Sartre. She went on to study at the Sorbonne, and became a teacher, eventually forming an open relationship with Sartre that lasted until his death. Choosing not to marry or have children, de Beauvoir devoted herself to writing and teaching. She is best known for her 1949 book The Second Sex, a detailed analysis of women’s oppression. Her famous phrase “One is not born but becomes a woman” advanced a social constructionist theory of gender and sexuality, which became highly influential on second wave feminism and later generations of queer studies. Her 1958 autobiography Memoirs of a Dutiful Daughter was also highly praised (and somewhat easier reading). She also produced essays on Existentialist theory, including The Ethics of Ambiguity and contributed to Sartre’s Being and Nothingness. She became active in the 1970s feminist movement, befriending her American compatriots Betty Friedan and Kate Millett. In 1971, she wrote and signed the Manifesto of the 343, a list of Frenchwomen who acknowledged having an abortion. Her open relationship with Sartre and other lovers overshadowed much of her work. She lived with Claude Lanzmann for much of the 1950s, and had a well-publicised affair with American writer Nelson Algren. She also had relationships with a number of her female students, including Natalie Sorokine and Bianca Lamblin. Her affair with the then-17 year old Sorokine led to her being suspended from her teaching position and charged with debauching a minor. She died in 1986 aged 78, and was buried next to Sartre.