The Blunderer was Highsmith's second book, written in between Strangers on a Train and The Talented Mr Ripley. It contains all of Highsmith's key themes: the sterility of marriage, the apparent ordinariness of evil, the soul-lessness of wealth. Like her two more famous books, it is also structured around the love-hate relationship between two men, one an all-American WASP, the other an obvious psychopath. In The Blunderer, the WASP is lawyer Walter Stackhouse; the psychopath is book dealer Melchior Kimmel.
Walter is married to Clara, a controlling and neurotic suburban housewife. Clara is unpleasant to everyone except her irritating terrier, Jeff. Walter tells Clara that he wants a divorce and Clara tries to commit suicide. When Clara is recovering, Walter begins to fantasise about killing his wife. About this time, he notices an unsolved murder case in the newspaper. Melchior Kimmel's wife was killed while she was waiting at a rest stop during a bus journey. At the novel's outset, the reader is told how Kimmel lured his wife away from the rest stop and strangled her. Walter visits Kimmel's bookshop out of curiosity and places an order for a book. Clara then takes a bus journey to see her dying mother. She never arrives; her body is found at the bottom of a cliff. Although Walter didn't kill her, he is glad she is dead, particularly as he has fallen in love with a neighbour, Ellie Briess. A local police officer, Corby, begins to investigate the case. He notices a resemblance between Clara's suicide and the death of Melchior Kimmel's wife. The rest of the book concentrates on Corby's investigations and Walter's gradual mental breakdown.