When rumors of a new disease swept the corridors of NIH in early 1981, Biggar was a skeptical young epidemiologist at the National Cancer Institute. "It can't be true." he thought. He was wrong. Within weeks, he dropped all his research to throw himself into the maelstrom of the unknown. By September 1981, he made plans to set up the first-ever cohort of gay men designed to study this epidemic in Denmark reporting some of the earliest evidence that AIDS came from an infection. He didn't stop there. We follow his efforts to find the cause, then see through his eyes the French/NCI feud over the discovery of HIV and the aftermath. Then he used the new tests in Africa to track down the reality of HIV in bush hospitals and their largest cities to establish the staggering dimensions of this problem, where it came from, and how it spread to become a global pandemic. His story started in 1981 and spans nearly four decades when scientists worked desperately to understand what seemed impossible. Written from field notes made as he worked, he fills it with anecdotes and stories from friends and colleagues all over the world. You are with him at every moment, sorting out the politics and personalities he faced and making decisions, right or wrong, in the urgency of the moment. This story of HIV/AIDS science is rich in detail and offers insight into how scientists around the world brought this terrible crisis under control.