"The Second Sex" is a foundational text in feminist philosophy written by Simone de Beauvoir in 1949. The book explores the construction of women's identity and the societal roles imposed on them, arguing that women have historically been defined as the "Other" in relation to men. De Beauvoir examines various aspects of women's lives, including biology, psychoanalysis, and history, to illustrate how these factors contribute to their oppression. The work is divided into two main parts: "Facts and Myths" and "Woman as Other." In these sections, de Beauvoir critiques the cultural narratives that shape women's experiences and advocates for women's liberation through existentialist principles. Her assertion that "one is not born, but rather becomes, a woman" emphasizes the social conditioning that influences gender identity.