A New York Times bestseller! The untold story of the eccentric Wall Street tycoon and the circle of scientific geniuses who helped build the atomic bomb and defeat the Nazis—changing the course of history.

Legendary financier, philanthropist, and society figure Alfred Lee Loomis gathered the most visionary scientific minds of the twentieth century—Albert Einstein, Werner Heisenberg, Niels Bohr, Enrico Fermi, and others—at his state-of-the-art laboratory in Tuxedo Park, New York, in the late 1930s. He established a top-secret defense laboratory at MIT and personally bankrolled pioneering research into new, high-powered radar detection systems that helped defeat the German Air Force and U-boats. With Ernest Lawrence, the Nobel Prize–winning physicist, he pushed Franklin Delano Roosevelt to fund research in nuclear fission, which led to the development of the atomic bomb.

Jennet Conant, the granddaughter of James Bryant Conant, one of the leading scientific advisers of World War II, enjoyed unprecedented access to Loomis’ papers, as well as to people intimately involved in his life and work. She pierces through Loomis’ obsessive secrecy and illuminates his role in assuring the Allied victory.