Two volumes, about a thousand pages, published in 1949 and selling twenty-two thousand copies in the first week. The Vatican put it on the Index. It is the founding text of second-wave feminism and it is a work of philosophy doing something philosophy had not done: taking a situation half the species lives in and asking what it is like from inside.

The question

Not what is woman — she refuses that. The question is why the position has been so durable.

Other subordinated groups can point to an event: a conquest, a migration, a change in production. Women cannot. There was no time before, no homeland, no moment it began, and women are distributed through every class and household rather than gathered where they might organize. They live with the people who benefit from their position.

Her frame: man has been posited as the universal, the neutral case, the human being as such. Woman is defined relative to him and not reciprocally. She is the Other — and, uniquely among Others, has largely accepted the account.

The sentence

On ne naît pas femme: on le devient. One is not born, but rather becomes, a woman. It opens Volume II and it is the most consequential sentence in twentieth-century feminism.

The claim is not that biology is irrelevant — Volume I spends its opening chapters on biology and takes it seriously. It is that biology does not deliver a destiny; what a female body means is produced by a civilization, and the producing can be traced. Volume II traces it, through childhood, adolescence, sexual initiation, marriage, motherhood and old age, as a sequence of situations that make a person into a woman as that society understands one.

The sex–gender distinction that later feminism formalized is this sentence being unpacked. She did not use the word gender.

What reading it is like

Long, uneven, and much more readable than its length suggests.

Volume I is the survey — biology, psychoanalysis, historical materialism, then history, then the myths, with a long section on how five male writers constructed women. The critiques of Freud and of Engels are sharp. The history is the datedest part.

Volume II is the reason to read it. The phenomenology of a life as it is actually lived — the chapters on the young girl, on marriage, on motherhood — is the best of her writing and is where almost everything later feminism took comes from.

Where to start: the Introduction to Volume I for the argument, then the opening of Volume II, then the chapter on the young girl. That is about a hundred and fifty pages and it is the book.

The translation problem, which matters

The English edition everyone read from 1953 to 2009 was made by H. M. Parshley, a retired zoologist with limited French, under a publisher's instruction to cut. He removed roughly ten per cent — including a large part of the history and many of the women named in it — and rendered her philosophical vocabulary inconsistently, translating pour-soi and en-soi as ordinary English and so making a technical argument read as loose prose.

For fifty years the standard English complaint that the book is unsystematic was, in part, a complaint about Parshley. The Borde and Malovany-Chevallier translation of 2009 is complete and keeps the philosophical terms. Anything written about the English text before 2010 should be read with that in mind.

Key passages

Volume I, Introduction — woman as the Other; why the position has no history of its beginning.

Volume I, Part 1 — the treatments of biology, psychoanalysis and historical materialism, each taken seriously and each found insufficient.

Volume I, Part 3 — the myths; the chapter on five writers.

Volume II, opening — one is not born, but rather becomes, a woman.

Volume II, Part 1, "The Young Girl" — adolescence as the point at which the situation is imposed and taken up.

Volume II, Part 2, "The Married Woman" — marriage, and the analysis of housework as labor that is undone daily and so produces nothing.

Volume II, Part 4, "Toward Liberation" — the argument that economic independence is necessary and not sufficient.

What is contested

Whether it universalises from one life. The book's woman is largely bourgeois, French, white and educated, and the claim to describe a condition is made from a narrow vantage. This is the standard and largely accepted criticism, and it is where intersectional critique starts.

Its treatment of motherhood. She describes maternity in terms that many readers, including sympathetic ones, find close to revulsion, and the account of pregnancy as an alienation of the body is the most contested part of the book.

Whether the solution is to become more like men. The liberation argued for is participation in work, projects and transcendence as men have had them, and later feminists asked whether that accepts the male standard as the human one rather than questioning it.

How much is Sartre's. Less than was assumed for fifty years. The situated account of freedom the book runs on is Beauvoir's own, worked out in The Ethics of Ambiguity two years earlier, and it is the point at which she departs from him rather than applies him.