Nigel West 
MI6: British Secret Intelligence Service Operations, 1909-1945 [PDF ebook] 

The author of GCHG describes covert missions that "are worthy of spy fiction, but the entire book is utterly fascinating and informative. Brilliant!" (Books Monthly)Written by the renowned expert Nigel West, this book exposes the operations of Britain’s overseas intelligence-gathering organization, the famed Secret Intelligence Service, MI6, and traces its origins back to its inception in 1909. In this meticulously researched account, its activities and structure are described in detail, using original secret service documents.The main body of the book concerns MI6’s operations during the Second World War, and includes some remarkable successes and failures, including how MI6 financed a glamorous confidant of the German secret service; how a suspected French traitor was murdered by mistake; how Franco’s military advisors were bribed to keep Spain out of the war; how members of the Swedish secret police were blackmailed into helping the British war effort; how a sabotage operation in neutral Tangiers enabled the Allied landings in North Africa to proceed undetected; and how Britain’s generals ignored the first ULTRA decrypts because MI6 said that the information had come from "a well-placed source called BONIFACE."In this new edition, operations undertaken by almost all of MI6’s overseas stations are recounted in extraordinary detail. They will fascinate both the professional intelligence officer and the general reader.The book includes organizational charts to illustrate MI6’s internal structure and its wartime network of overseas stations. Backed by numerous interviews with intelligence officers and their agents, this engaging inside story throws light on many wartime incidents that had previously remained unexplained."[An] extraordinary book." -The Daily Telegraph"Fascinating reading." -Firetrench