The 70th anniversary of the completion of the Maud Committee Report falls in 2011, the year of this book’s completion. As discussed in Chapter 2, the Maud Committee oversaw a research project conducted in great secrecy by the British government in 1940-41. It ended by confirming the prediction of two émigré scientists, Otto Frisch and Rudolf Peierls, that a militarily useful atomic bomb could be constructed from modest quantities of fissile material obtained by enriching natural uranium. Shared with the US government in autumn 1941, it was this report, together with the United States’ entry into the war after Pearl Harbor, that galvanized the Manhattan Project. Without its findings, it is unlikely that a functioning atomic bomb could have been available before the end of the Second World War, in which case the destruction of Hiroshima and Nagasaki would not have happened. This is not to imply that the development and production of nuclear weapons would have been foregone and that their later use would have been avoided. But the history recounted in these pages would undoubtedly have been different.