Simone de Beauvoir was a 20th century French philosopher and author who was a major figure in feminist philosophy and existentialism. In her groundbreaking 1949 book The Second Sex, she argued that women are viewed as the "Other" in a male-dominated society, with men seen as the subject or absolute. She believed women should define themselves independently of men rather than in relation to them. Taking a man's last name in marriage and lack of opportunities for women perpetuated an inferior meaning of life for women in society at the time.