How and why did a theoretical physicist, far from politics, the creator of Soviet thermonuclear weapons, turn into a staunch defender of human rights? Was the hydrogen bomb created by our scientists independently or with the help of intelligence? What did science and freedom mean to Andrei Sakharov, how did he look at his fate and what did he think about the relationship between scientific research, political activity and religious feeling? These questions are answered by historian Gennady Gorelik, the author of many books and articles on the history of Russian science. The first complete biography of Sakharov is based on recently declassified documents and testimonies of dozens of people who knew the hero of the book as a student, scientist and human rights activist, at work and in the family circle. The publication is supplemented with rare photographs.[Adapted for AlReader]