INTREPID is the code name Winston Churchill gave to William Stephenson (no relation to this book's author) when assigning him to organizing British Security Coordination in 1940. BSC was the top secret-operations center for the Allies and Stephenson the supremely trusted liaison between the newly empowered prime minister and Roosevelt. A Canadian industrialist-scientist, Stephenson had early become aware of Germany's rearmament and begun a personally financed private spy system which he later offered to Churchill. Long before Pearl Harbor, Stevenson suggests, Roosevelt entered into clandestine operations with Stephenson which could have resulted in impeachment (these included allowing Nelson Rockefeller a comparatively free hand as our top spy chief in South America). Stephenson's greatest coup was the theft of a German ENIGMA code-machine which became the basis for ULTRA, the Nazi device whose secret messages made Hitler's every move perfectly clear to the British. No simple summary can convey the excitement and achievements of BSC's crew of agents and counteragents--this is the most popular spy book among such comparable works as Brown's Bodyguard of Lies (1975) and Winterbotham's The Ultra Secret (1974). There are even excerpts from James Bond novels (Ian Fleming worked under Stephenson for British Naval Intelligence) which duplicate BSC activities and they show the maddest fiction to be paler than truth.