During World War II, dozens of women Cambridge University students worked around the clock in complete secrecy to crack Nazi codes, but only now are the unsung heroes getting recognition. At least 77 women from the women-only Newnham College were drafted to Bletchley Park, the code-breaking centre north of London, during the conflict. It was there that mathematician Alan Turing decoded messages encrypted by the Nazis' Enigma machine, in particular those sent by German U-boats submarines in the North Atlantic. Historians widely acknowledge that Bletchley played a key role in bringing down Adolf Hitler. But the story of the Cambridge...