Lydia Millet's novel tells an extraordinary story of the three scientists who formed the core of the team that developed the atomic bomb. With the exploding of the first bomb in Nevada, Robert Oppenheimer, Leo Szilard and Enrico Fermi are transported to today's America. As they gradually realise what has happened to them, all three are consumed by guilt at the impact of their brainchild. At first the only person who believes they are who they say they are is a librarian who recognises Oppenheimer from his photograph in a book. With her they travel to Hiroshima, Nagasaki and Bikini, in the footsteps of the bomb itself, on a journey of atonement which eventually leads them to organise a protest march from Nevada to Washington DC. As the media increasingly respond to their presence and their claims, an ever stranger crowd of followers gather round the three scientists, first of young leftists, subsequently of fundamentalist Christians, some of whom see Oppenheimer as Messiah, leading to a climactic apothesis that is both utterly surreal and movingly beautiful. Oh Pure and Radiant Heart is no more a SF novel than The Time-Traveller's Wife. Instead it is a powerful and original fiction of responsibility and guilt, today's America, and the peculiar terrors of our nuclear world.