Georges Abramovich Koval is a unique person. His life path passed through the epicenter of the key event of the 20th century - the creation of nuclear weapons in both the USA and the USSR. For his invaluable contribution to the timely creation of the Soviet atomic bomb, he was posthumously awarded the title of Hero of Russia. The materials for writing the book included biographical articles and books about him, documents from Russian and American archives, documents from his family archive, conversations and interviews with people who knew him, as well as personal impressions of the author who communicated with him during the last 40 years of his life. Second revised and expanded edition.