Simone de Beauvoir (1908–1986) was a French existentialist philosopher, intellectual, and social theorist best known for her writings on existentialist ethics and feminist existentialism, as well as for her infamous polyamorous relationship with fellow French existentialist Jean-Paul Sartre. World-renowned for her metaphysical novels She Came to Stay and The Mandarins, de Beauvoir also wrote a number of essays on philosophy, politics, and social issues. Her diverse writings go on to include biographies, as well as her four-volume autobiography, made up of Memoirs of a Dutiful Daughter, The Prime of Life, Force of Circumstance, and All Said and Done. In addition to her philosophical writing, de Beauvoir was an ardent feminist, her most famous philosophical work being The Second Sex, which is consistently referenced in the study of feminism.