Agent M: The Lives and Spies of MI5’s Maxwell Knight

British popular historian and biographer Hemming (The Ingenious Mr. Pike) revisits the life of Maxwell Knight in the first biography of the 20th century’s leading MI5 spymaster. Knight was an eccentric figure who “possessed an unparalleled ability to turn unqualified men and women—bankers, secretaries, lawyers, booksellers—into reliable and consistently productive agents.” During the 1920s and ’30s, Knight used this ability to infiltrate and render innocuous the British Fascist movement, under the leadership of first William Joyce (later Lord Haw-Haw) and then Oswald Mosley. Knight had for some years been attracted to fascism himself and might have tipped off his old friend Joyce that he was about to be apprehended before Joyce fled to Germany in August 1939. Hemming writes far more briefly about Knight’s less successful postwar effort, including his recruitment of John le Carré to identify communist infiltrations of British institutions. The book is clearly written and well researched, though Hemming occasionally stumbles, as when he gets distracted by the work of some of Knight’s less effective agents in the early 1930s. Still, this in-depth introduction illuminates a largely forgotten man of antidemocratic tendencies who played a key role in keeping Britain secure and democratic for much of the interwar and early postwar periods. (May)