A volume in the British Government's Official History of Intelligence in the Second World War, the book has been written by a master historian renowned for his eloquence as well as for his learning.

The success of these operations can be measured by the fact that by 1943 the Germans were almost wholly dependent on double agents for news of what was going on in the United Kingdom; intercepted and decrypted radio traffic showed the Allies how extensively the enemy was accepting disinformation and acting on it. In Britain, extremely tight communications security made possible the apprehension and control of virtually all active enemy agents.

Sir Michael Howard explains how the British were able to deceive the Germans about the strategic intentions of the Allies and make them greatly overestimate Allied resources. Here is the most authoritative account available of such classic deception operations as Operation Mincemeat, which preceded the invasion of Sicily; the nonexistent U.S. Army group that pinned down an entire German Army in the Pas de Calais until Montgomery's forces had achieved a secure foothold in Normandy; and the amazing trick played on the German intelligence authorities by the great double agent Garbo.