When friends mean less than plots ... a flawed portrayal of the noir novelist as a figure bordering on the grotesque

In middle age Patricia Highsmith perfected a particularly ghastly party trick. Invited to a swanky London dinner, she arrived with 30 “pet” snails in her handbag which she proceeded to tip out on to the table. The snails immediately started their determined looping across the linen tablecloth, leaving behind a lattice of silvery slime. Everyone, including Highsmith herself, pretended not to notice.

If Highsmith were simply a sociopathic alcoholic, and there’s plenty of evidence to suggest that she was, then this anecdote would be picturesque but not important. What makes it matter is the way it captures the uncanny menace at the heart of her most successful novels, Strangers on a Train (1951) and The Talented Mr Ripley (1955). There’s nothing intrinsically evil about snails, handbags, linen tablecloths or even swish dinner parties. But put them in the right, or rather wrong, order and you have the kind of insidious nightmare that becomes impossible to shake off. Graham Greene, an early fan of Highsmith’s, described her as “the poet of apprehension”. You could not read her, he said, without constantly checking over your shoulder.