This 600-plus-page book answers many of the questions that any le Carre fan might have. The brilliant, rumpled, vulnerable George Smiley, in case you ever wondered, was based mainly on Vivian Greene, rector of Lincoln College, Oxford, and MI5 talent-spotter. The matter of Smiley’s wife, the promiscuous, cheating Ann, is more complicated: the name of le Carre’s own first wife happened to be Anne. But it was le Carre himself who did the cheating, prolifically and shamelessly (at one time even cuckolding his best friend), which led to the break-up of le Carre’s marriage, as well as to the writing of The Naive and Sentimental Lover, his worst novel. If there’s a flaw in this book, however, it is the fact that Sisman appears to hold back from any kind of literary assessment of le Carre’s work. So is he a writer of serious literary fiction (as one school of thought, led by Philip Roth, holds)? Or is he just a glorified ‘genre writer’ of spy thrillers (as another, led by Salman Rushdie, insists)?