In 1943, Robert Oppenheimer, the brilliant, charismatic head of the Manhattan Project, recruited scientists to live as virtual prisoners of the U.S. government at Los Alamos, a barren mesa thirty-five miles outside Santa Fe, New Mexico. Thousands of men, women, and children spent the war years sequestered in this top-secret military facility. They lied to friends and family about where they were going and what they were doing and then disappeared into the desert. The women came despite the Army's initial objections, as Oppenheimer insisted that would be the only way to recruit the world-class physicists and keep them reasonably sane and content during the years it would take to create this revolutionary new weapon. Conant shows how the stringent security, lack of privacy, spartan living conditions, and loneliness of the isolated mountain hideaway drove some residents to the brink of despair. Yet only a handful gave up and left. Through the eyes of a young Santa Fe widow who was one of Oppenheimer's first recruits, we see how, for all his flaws, he developed into an inspiring leader and motivated all those involved in the Los Alamos project to make a supreme effort and achieve the unthinkable.