Eighty years ago today, an American B-29 bomber dropped an atomic bomb on the Japanese city of Hiroshima. It was the dawn of the atomic age, but the birth of the bomb can be traced beyond the deserts of New Mexico to Britain, five years earlier. A copy of a hand-typed document, now in the Bodleian library in Oxford, is the first description of an atom bomb small enough to use as a weapon. The Frisch-Peierls Memorandum was written by two nuclear physicists at the University of Birmingham in 1940. Image: The memorandum is the first description of an atom...