If you want to know what John le Carré was really like, “The Pigeon Tunnel” won’t help you. The master of the spy novel, who died in 2020, took his secrets to the grave.

What you can get, instead, from “The Pigeon Tunnel” — a documentary portrait by Errol Morris — is a sense of what it would have been like to be in a room with le Carré, to be sitting at a table with him, listening to him tell stories. The film presents us with a charming, handsome, well-spoken and phenomenally engaging old man who, for reasons that are hard to pin down, just doesn’t seem trustworthy.

If the documentary has a flaw, it’s that it doesn’t illuminate precisely what about le Carré makes us feel uneasy about him. Morris gives us the pleasure of the man’s company, but he doesn’t get enough for a full portrait. This is in contrast to “The Fog of War,” his film about Robert MacNamara, and “The Unknown Known,” about Donald Rumsfeld. In those films, even though Morris didn’t go out of his way to reveal his own opinions, a detailed portrait emerged of the inner workings of both men.

With le Carré, we come away with considerably less, though his very elusiveness holds our attention. He seems intent that we like him, and we do. And we want to believe every word he says. He is an American’s idea of the perfect English gentleman, even though he was from modest means, and his father was a professional con man.

Filmed in 2020, when le Carré — real name David Cornwell — was 88 years old, “The Pigeon Tunnel” films le Carré seated at one side of a table, as he’s being interviewed by Morris, who remains off camera. As sharp as ever and apparently healthy — though he would die of pneumonia at the end of the year — le Carré talks about his peculiar childhood with a charming, mendacious father.

In vague terms, he discusses his own brief career as a British spy and makes interesting points about the kind of personality that governments recruit for espionage work. Ideally, spies are “bad, but loyal” people with an early experience of independence from their families. He analyzes famous double agents and describes the joy of deception, the feeling of power that comes from misleading everyone.

The novelist’s first great success — with 15 million copies sold — was “The Spy Who Came in From the Cold,” which was inspired by the building of the Berlin Wall and the subsequent human misery it produced. In the documentary, he calls the wall “the most obscene symbol of the insanity of the human struggle.”

At the time the book came out, in 1963, the Western world had gone crazy for James Bond, both in print and onscreen. But whereas Bond was someone the reader might aspire to be, a spy’s world in le Carré’s novel was ugly, bitter and compromised. As le Carré puts it, people would read his books and think, “I hope that isn’t me.” When Morris calls him an “exquisite poet of self-hatred,” the author seems pleased.

勒卡雷的粉丝,“鸽子隧道”是一个must-see, but the film will also be useful to people wanting an introduction to his work. Sometimes writers will write adventure stories, and then you’ll see the writer and realize that the novel was just some bookish fellow’s fantasy. But to his credit, le Carré wasn’t like that. He looked as knowing, urbane and labyrinthine as the worlds he depicted.

Reach Mick LaSalle: mlasalle@sfchronicle.com