“What is a woman“ is a very good and easy-to-read reuse of Beauvoir‘s and Merleau-Ponty’s existentialist understanding that you experience life as a “lived body“ / as “a situation“, whose biology affects what you could do but does not determine what you do, with a history and in a social setting, to argue the sex/gender distinction is useless in trying to answer the question of what is a woman or a man. You certainly can’t infer social norms from biology (here the sex/gender distinction IS useful). Moi‘s answer to the question of what is a woman is that it depends on the situation, and that there’s no one-size-fits-all answer. Regarding trans people, Moi argues (writing in 1999 and before same-sex marriage was legal) being a woman for the purposes of getting married is not the same as being a woman for the purpose of participating in a lesbian activist group. But she also recognises the issue of trans people as difficult and in need of more input, above all from trans people themselves, and says this shouldn’t stop us understanding “easy cases“.