The development of Simone de Beauvoir's notion of self in both her philosophical and autobiographical writings is analyzed in this volume. Two ideas of the self are isolated: the existential notion of the self and the gendered self, which she developed in the Second Sex , and which represents a major departure from existential philosophy. Beginning with a study of her early essays, the author proceeds to discuss Beauvoir's major philosophical works and her autobiographical writings where three personae emerge ― the child, the woman in love, and the writer. This analysis highlights the innovative quality of Beauvoir's thought. It also shows that writing an autobiography can be a philosophically inventive enterprise and one in which Beauvoir created her most profound analysis of the self.