Simone de Beauvoir made significant contributions to feminist philosophy, particularly with her groundbreaking text "The Second Sex." In this work, she examined the societal constructs surrounding gender and challenged the notion of women as "the Other." Her explorations of existentialism and subjectivity laid the groundwork for modern feminist theory, asserting that one's identity is shaped by social and cultural contexts. Beauvoir's famous declaration that "one is not born, but rather becomes, a woman" emphasizes the importance of socialization in gender roles. Her ideas continue to influence feminist discourse, advocating for autonomy and liberation in a patriarchal society.