He was one of the most brilliant minds. She was his lifelong companion who pioneered feminism. Jean-Paul Sartre and Simone de Beauvoir were perhaps the most influential couple of the 20th century. Their legendary love pact - they never married but swore mutual devotion to each other with the freedom to have affairs - was an attempt to overthrow the stifling hypocrisy that, for so long, had dictated most people's lives. Always pushing new boundaries, they explored their thoughts in novels, plays and philosophical works. It earned Sartre the world's greatest literary accolade, the Nobel Prize. Yet he refused to...