It’s likely that Ian Fleming’s M was a nod to Maxwell Knight, an MI5 spymaster of renown in the circles traveled by James Bond’s author. An eccentric, jazz-loving Englishman, Knight worked for Britain’s domestic intelligence service from 1932 through the Cold War, all the while penning crime novels and zoological works. He was, briefly, John le Carré’s boss and became the model for that author’s Jack Brotherhood. Using recently declassified files and a host of secondary sources, Henry Hemming reconstructs the life of this mysterious figure. His prose is sometimes clichéd but also sometimes funny as he investigates a man with an outstanding knack for charm and deception.