The period from 1933 to 1943 was one of the darkest and most chaotic in human history, as the Second World War unfolded with unthinkable cruelty. It was also a crucial decade in the dramatic, intersecting lives of some of history's greatest philosophers. There were four women, in particular, whose parallel ideas would come to dominate the twentieth century--at once in necessary dialogue and in striking contrast with one another.

Simone de Beauvoir, already in a deep emotional and intellectual partnership with Jean-Paul Sartre, was laying the foundations for nothing less than the future of feminism. Born Alisa Rosenbaum in Saint Petersburg, Ayn Rand immigrated to the United States in 1926 and was honing one of the most politically influential voices of the twentieth century. Her novels The Fountainhead and Atlas Shrugged would reach the hearts and minds of millions of Americans in the decades to come, becoming canonical libertarian texts that continue to echo today among Silicon Valley's tech elite. Hannah Arendt was developing some of today's most important liberal ideas, culminating with the publication of The Origins of Totalitarianism and her arrival as a peerless intellectual celebrity. Perhaps the greatest thinker of all was a classmate of Beauvoir's: Simone Weil, who turned away from fame to devote herself entirely to refugee aid and the resistance movement during the war. Ultimately, in 1943, she would starve to death in England, a martyr and true saint in the eyes of many.

Few authors can synthesize gripping storytelling with sophisticated philosophy as Wolfram Eilenberger does. The Visionaries tells the story of four singular philosophers--indomitable women who were refugees and resistance fighters--each putting forward a vision of a truly free and open society at a time of authoritarianism and war.