Monique Wittig is probably best known for her radical statement: Lesbians are not women. The complex theoretical construct behind this sentence is mostly unknown. This work tries to revive Wittig's radical thoughts on language and society as developed in 'The Straight Mind', a collection of her essays. The French author not only criticises the oppressive nature of heteronormativity and patriarchy ¿ its mechanisms and its impact on society and individuals likewise ¿ but also analyses language in regards of how a world dominated by men influences the reality of gendered beings in general, and women and lesbians in particular. Since Wittig places great importance on the change of language, a detailed analysis of her short story 'The Garden' forms part of this book. Wittig's radical theories try to show a way out of a society which is hierarchically structured on the basis of the categories of sex, which divide human beings into men as the appropriators of the universal and women as an oppressed class. The paper presents her profound theories before evaluating them, in order to be able to conclude why she is absent from much of today's feminist, queer and gender debate.