In The Pigeon Tunnel, Errol Morris’ new documentary about John le Carré, the novelist explains that he never underwent psychoanalysis because he was afraid that too much self-knowledge would crush his creativity. Le Carré—real name David Cornwell—was the most celebrated spy novelist of his time (arguably of all time). He was also a self-confessed chronic fabulist. Lying, he stated more than once, is the essence of both espionage and fiction writing. That claim about never undergoing analysis? It might be technically true. Cornwell’s biographer, Adam Sisman, however, describes coming across, while working among le Carré’s archives, a “long document that...