The insane fascinate novelists, and this is understandable. The use of a madman as a narrator or protagonist offers a whole host of possibilities not open to the sane: the chance to explore synesthesia, delusion, sadism, obsession, and even, in the case of Benjy in “The Sound and the Fury,” a strange moral innocence. It offers, in short, an opportunity for writers to investigate the extremes of the human condition, in a direct, immediate way. This is particularly true of the criminally insane: think of Smerdyakov in “The Brothers Karamazov,” or Christian Moosbrugger, the rapist-murderer whose arrest and imprisonment form a central narrative thread in Robert Musil’s “The Man without Qualities.”

The Lebanese novelist, playwright, and critic (and sometime member of Fatah) Elias Khoury’s newly translated 2002 novel “Yalo” (Archipelago, 317 pages, $25) centers on such an extreme personality: Daniel Abyad, called Yalo. That Mr. Khoury has chosen to make a disturbed mind his focal point should not be surprising: His 1998 novel “The Gate of the Sun” focused on the inner life of its central character, a doctor in a Palestinian refugee camp. It’s somewhat puzzling, then, why — given this confluence of interest and skill — “Yalo” remains such a sketchy, thin, even trite book. One likely explanation is that it shows the strain of Mr. Khoury’s attempting to make Yalo himself into a quasi-mythic figure.

The novel’s plot is at once simple and difficult to distill, in large part because it reaches us mediated by a lunatic. Daniel Abyad is the son of an insane mother, an absent father, and a fanatically Christian grandfather. An ex-solider, he works as a security guard on the estate of a prosperous lawyer in Bellouna, Lebanon. The book narrates Yalo’s arrest, interrogation, and eventual confession to a number of rapes, acts of theft, and acts of political terrorism. Yalo insists, initially, on his innocence, but comes more and more to emulate his accusers’ point of view. His main antagonist, other than his faceless, nameless interrogators, is his ex-lover and longtime object of obsession, Shirin Raad, who made the initial charge of rape against him at the behest of her fiancé. Yalo eventually capitulates and is convicted by the court; the book’s final pages are a “transcript” of that verdict. Along the way, the story of his relations with Shirin is disclosed, as well as his traumatic youth in the hands of his crazed guardians.

A large part of the book’s deficiency lies in its prose. The language is heavy, repetitive, and given to mawkish lyrical flights. One might charitably suppose that this is an effort to render precisely the inner state of the book’s protagonist — who is himself a perseverator and something of a fantasist. But it’s hard to excuse passages such as the following, which details Yalo’s experience during a brutal interrogation session:

Blood, hawk, and pain. Suddenly his body left its owner and went to incalculable pains. He saw it fade away and sink into the pool of pain . . . Yalo felt that he had shed the hawk and taken on the tentacles of the cuttlefish, and the pain stopped. He saw how he grew eight arms and seventy million optic cells stretched across his limbs, and saw his female, Shirin, swimming to his side in the depths and he extended his fourth right arm to her, this arm was his sexual member, he pressed it into her feminine cavity, felt the eggs and fertilized them, and slept inside her.

We hardly fare any better when Mr. Khoury explicitly turns the narrative over to Yalo, by interlarding confessions and court documents into the book. Indeed, by the time the novel ends — not without undergoing a somewhat leaden metafictional shift that suggests that Yalo may have been narrating the entire time — our capacity for sympathy with the vagaries of Yalo’s mind has thoroughly been exhausted.

To be fair, Yalo has been translated from Arabic by Peter Theroux — a journalist and translator of Mahfouz and Abdelrahman Munif, among others — and it may well be possible to ascribe at least some of the prose’s flaws to the inherent difficulty of translation, particularly from a Semitic into a Romance language. But the book’s problems run deeper: Even with all of the plot’s intrigue, with all of Mr. Khoury’s elaborate interweaving of memory and desire, Yalo himself, the center of the book, never really commands our sympathy. He well might: scapegoated, tortured, victimized by the state and in a subtler way by his mother and grandfather, flawed but possessed of a childish sense of honor and innocence. But Mr. Khoury cannot do much more than make him a kind of Christ figure — physically beautiful and morally otherworldly — meant to depict the political sufferings of the Lebanese people at the hands of a brutal state.

Yet all Mr. Khoury can really muster to shore up this picture of Yalo is cliché, drawn from sources as various as Albert Camus (Yalo suffers from a total cognitive dysfunction similar to that afflicting the hero of “The Stranger”) to the Gospel of Mark (Yalo, at one point, walks or claims to have walked out on the Mediterranean). And though there are numerous echoes — and these can hardly be unintentional — of the passionate, violent, sexually conflicted Dmitri Karamazov both in Yalo’s character and in his legal tribulations, these serve only to point out the murky, amorphous nature of the figure Mr. Khoury has drawn. The summoning of lofty literary archetypes brings with it a requirement to make some new use of them, much as Dmitri Karamazov’s torments constitute an ironic, perverse mirroring of Jesus’s. Mr. Khoury, attempting to endow Yalo with a broad political significance, only excludes him from the horizon of our comprehension. Given the very real sufferings of both his nation and its citizens, Mr. Khoury’s failure is all the more damning.

Mr. Munson is online editor of Commentary.