Enthralling and enticing, a great work for amateur generalists and for historians, a triumph of the master-sleuth after great and petty sleuths, a search not deterred by senseless government secrecy defended "on . . . dotty grounds." The story begins with Victorian Britain, fastens on intercepts during both wars and the interwar period, insists that historians cannot write proper history without understanding the mutual eavesdropping that went on. The hero of intelligence was Churchill, who early on understood and revelled in Ultra; the great masters were the top people at Bletchley. Andrews takes the story right down to the Falkland Islands, grappling with the rival claims of secrecy versus the need for a democracy to be informed. He has written a splendidly readable, indispensable work on one of Britain's greatest defenses: her intelligence community, warts, failures and all.