["The Outsider" ("El túnel") is] a novel that leads us again into that favorite province of the romantic psychologist: the police blotter; and once again we are introduced to the literary confessional of the misunderstood criminal, the underground man. If, as one supposes, all murders are a kind of hallucination; if the thing one kills is, apparently, some extension of the self, then what we are fascinated by in a murder is the element it contains of suicide. This is, apparently, what Sabato wishes to say. The genuinely hallucinated man, driven to an explanation of his motives, can never actually explain his crime. He exists within the prison of his own hallucinated logic. He cannot penetrate the existence of another. He can only answer, when the victim questions him, "I have to kill you, Maria. You have left me alone." and, sobbing, drive the knife in. Nor will he be able to understand, later, why his apparently inevitable conduct should appear to others the action of a fool. The real relationships of others (for we never know whether Maria Iribarne has actually been unfaithful to Castel) remains hidden from him, as he remains hidden from himself….

Although it resembles Albert Camus's "The Stranger" in its devices and in its concern with human isolation, "The Outsider" is less impressive than the French novel. Perhaps the difference lies in the difference between an analysis of human motive and a poetry of human motive. Camus's novel contained the poetry; the Argentinian's seems arid and dry by comparison.