Up Front.

Ben Macintyre contributes a weekly column to The Times of London on history, art, politics, foreign affairs -- and espionage. Although he has never written a novel, his books are filled with colorful characters, from Adam Worth (''the real Professor Moriarty'') to Ian Fleming, creator of James Bond. The first volume of Macintyre's World War II espionage /trilogy, ''Agent Zigzag,'' featured a real-life criminal and double agent who played a pivotal role in the early part of the war. The second, ''Operation Mincemeat,'' told the story of a secret plan involving a corpse carrying forged papers in the run-up to the invasion of Sicily in 1943, a deception made famous by the film ''The Man Who Never Was.'' As Macintyre notes in his review of ''An American Spy,'' Olen Steinhauer's latest thriller, spying and fiction have always been intertwined. ''Spies often behave as if they're the actors in some peculiar drama of their own,'' he remarked in an e-mail. ''And their spymasters often think like novelists.'' Researching the final volume of his espionage trilogy, ''Double Cross: The True Story of the D-Day Spies,'' in the newly declassified files of M.I.5, the British secret service (which, as recently as 1997, ''did not, officially speaking, exist''), Macintyre discovered ample proof of this connection. ''The D-Day spies sound as if they have emerged from some particularly fantastic novel of the period: a bisexual Peruvian playgirl, a tiny Polish fighter pilot, a Serbian seducer, a wildly imaginative Spaniard with a diploma in chicken farming and a hysterical Frenchwoman whose obsessive love for her pet dog very nearly wrecked the entire deception.'' [ABSTRACT FROM AUTHOR]