Simone de Beauvoir (1908-1986) made important contributions to ethics, social philosophy, and the philosophy of the body, and was also a prize-winning novelist. Her book The Second Sex (1949) made a huge impact as part of the second wave of feminist thought. This accessible study examines Beauvoir's philosophy across all her works, including not only The Second Sex, The Ethics of Ambiguity and her essays, but also her novels, autobiography, travel diaries and memoirs. Her key ideas are analysed, including freedom and self-creation -- with special attention to their constraints and limitations - solidarity, and the role of other people in a person's existence. Her views of women's lived experience, motherhood, the body, illness, and death are related to our own time, with examples from current affairs, literature, cinema, and social media. The result is a fresh perspective on Beauvoir's philosophy and its enduring power to illuminate existential and social realities.