If diligence alone could guarantee an effective biography, this would be a masterwork. Ex-journalist Brown (Bodyguard of Lies, The Last Hero) seems to have canvassed every available shred of documentary evidence bearing on Menzies, the enigmatic chief of Great Britain's Secret Intelligence Service (now MI6) from 1939 to 1952. As ""C"", the role model for Ian Fleming's M, and le CarrÃ‰'s Control probably would have agreed, however, there's a vast difference between information and intelligence. Thus, while the author offers a wealth of intriguing material, it's too often submerged in a welter of conjectural analysis, tangential anecdotes, tedious excerpts from such records as have come to light, and exulpatory conclusions. The only newsman ever known to have interviewed Menzies (in 1964, four years before he died at 77), Brown has obvious respect and affection for the aristocratic spymaster whose existence remains barely acknowledged by officialdom. Scion of a Scots family that had prospered in distilling, Menzies enjoyed a privileged but by no means pampered youth. Going directly from Eton into an upscale regiment, he Compiled a valorous combat record in WW I. Transferring to intelligence before' the Armistice, he had little difficulty in achieving rank, thanks in part to his ties to ""the mink and manure set."" Three months into WW II, Menzies was appointed head of SIS over Churchill's initial opposition. During his stewardship, there were setbacks as well as triumphs. On the plus side of the ledger, the service spearheaded the breaking of Nazi Germany's military and diplomatic codes, permitting ""C"" to provide the Allies with confident assessments of Axis intentions. On the other hand, he engaged in savage turf battles with SOE (Special Operations Executive), vied constantly with Wild Bill Donovan's OSS, and was thoroughly snookered on the eve of his accession by Abwehr agents who contrived the Venlo incident. In the heat of the Cold War, moreover, Menzies was in the eye of the Kim Philby storm. Brown (who gives his subject the benefit of almost every doubt) speculates, none too convincingly, that a guileful ""C"" engineered the Cambridge-educated traitor's belated defection (in 1963) to gain another Kremlin Source. A dogged rather than definitive or distinguished account, then, of a thrice-married mystery man whose professional and personal lives seem likely to remain a closed book for many years to come. The 814-page text has photographs, maps, and a glossary (not seen).