What ought to be the definitive biography of ‘the father of the atom bomb’ has been long awaited in more ways than one. Martin Sherman started work on the book in 1979, and it was eventually published in the United States in 2005. But it failed to find a British publisher at that time, and only now, garlanded with a Pulitzer Prize, has it formally crossed the Atlantic. As is all too often the case, the anticipation was better than the reality: American Prometheus is a fine, scholarly work, but it is not, after all, the definitive biography of Robert Oppenheimer. There is too much politics and too little science, even allowing for the huge political importance of the man and his work. And the man himself remains in many ways an enigmatic figure.