**An epic story of science and technology at the very limits of human understanding: the monumental race to build the first atomic weapons.** Rich in personality, action, confrontation, and deception, *The First War of Physics* is the first fully realized popular account of the race to build humankind’s most destructive weapon. The book draws on declassified material, such as MI6’s Farm Hall transcripts, coded soviet messages cracked by American cryptographers in the Venona project, and interpretations by Russian scholars of documents from the soviet archives. Jim Baggott weaves these threads into a dramatic narrative that spans ten historic years, from the discovery of nuclear fission in 1939 to the aftermath of ‘Joe-1,’ August 1949’s first Soviet atomic bomb test. Why did physicists persist in developing the atomic bomb, despite the devastation that it could bring? Why, despite having a clear head start, did Hitler’s physicists fail? Could the soviets have developed the bomb without spies like Klaus Fuchs or Donald Maclean? Did the allies really plot to assassinate a key member of the German bomb program? Did the physicists knowingly inspire the arms race? *The First War of Physics* is a grand and frightening story of scientific ambition, intrigue, and genius: a tale barely believable as fiction, which just happens to be historical fact.