The remarkable life of one of the most influential men of the greatest generation, James B. Conant - a savvy architect of the nuclear age and the Cold War - told by his granddaughter, New York Times best-selling author Jennet Conant.

James Bryant Conant was a towering figure. He was at the center of the mammoth threats and challenges of the 20th century. As a young eminent chemist, he supervised the production of poison gas in WWI. As a controversial president of Harvard University, he was a champion of meritocracy and open admissions. As an advisor to FDR, he led the interventionist cause for US entrance in WWII. During that war, Conant was the administrative director of the Manhattan Project, oversaw the development of the atomic bomb, and argued that it be used against the industrial city of Hiroshima in Japan. Later, he urged the Atomic Energy Commission to reject the hydrogen bomb and devoted the rest of his life to campaigning for international control of atomic weapons. As Eisenhower's high commissioner to Germany, he helped to plan German recovery and was an architect of the United States' Cold War policy.

Now New York Times best-selling author Jennet Conant recreates the cataclysmic events of the 20th century as her grandfather James experienced them. She describes the guilt, fears, and, sometimes, regret of those who invented and deployed the bombs and the personal toll it took. From the White House to Los Alamos to Harvard University, Man of the Hour is based on hundreds of documents and diaries and interviews with Manhattan Project scientists, Harvard colleagues, and Conant's friends and family, including her father, James B. Conant's son. This is a very intimate, up-close look at some of the most argued cases of modern times - among them the use of chemical weapons, the decision to drop the bomb, Oppenheimer's fate, the politics of postwar Germany, and the Cold War - the repercussions of which are still affecting our world today.