Born in Paris, de Beauvoir studied at the Sorbonne, and became famous when she wrote the classic study of women's oppression Le Deuxième Sexe (1949, trs. as The Second Sex, 1953). This is the first influential work of feminist philosophy to distinguish between biological sexual difference and the socially imposed categories of gender. Before that her concern was to develop a non-solipsistic, social existentialism, in which an individual's freedom is only achieved in communication with others equally free. De Beauvoir's long association with Sartre is not usually regarded as an example of this equality. It culminated in Les Cérémonies des adieux (1981, trs. as Adieux: a Farewell to Sartre, 1984), an account of the last years of Sartre's life published a year after his death. Autobiographical writings include Mémoires d'une jeune fille rangée (1958, trs. as Memoirs of a Dutiful Daughter, 1959) and Une morte très douce (1964, trs. as A Very Easy Death, 1964).