UNFORGETTABLE.(Oblivion)(Book Review)

In the long, groping, and haphazard drama of evolution, human consciousness is a recent and precarious acquisition. Our anxiety at its precariousness has much to do with our increasing life expectancy: living longer physically, what can we expect to experience mentally? Neurological impairment is something we're all too likely to know firsthand, and Peter Abrahams's suspense novel "Oblivion" (William Morrow; $24.95) makes of this condition something rich and strange: an investigation into "lost time, like some dark forest in a fairy tale." The protagonist is a forty-two-year-old Los Angeles private detective named Nick Petrov, who, at first unknowingly, suffers from a form of brain cancer ("glioblastoma multiform") whose symptoms he attempts to rationalize or conflate with the progress of his current investigation. Unlike the morbidly compelling case studies of Oliver Sacks's "The Man Who Mistook His Wife for a Hat" (1970), which are narrated from outside the afflicted individuals, "Oblivion" immerses us in Petrov's assailed consciousness as he navigates his way through a Dali landscape of baffling clues, memory lapses, and visual hallucinations in an attempted reconstruction of personality that is simultaneously a search for a missing fifteen-year-old girl: "Find the girl and live."

It is a turn of the screw that Petrov, the Russian-born son of a former K.G.B. agent turned C.I.A. contractor, is a celebrated private investigator known for his success in finding missing people, and a further turn of the screw that, in his search for the girl, the clues Petrov begins to discover in his own possession overlap ominously with a seemingly solved case of his from twelve years earlier: "What happens if when all your energy is focused on a shaky future, the past suddenly gets shaky, too?" The vividly delineated physical terror of Petrov's predicament is compounded by the psychological terror of his loss of self in a recurring phrase wielded by Abrahams to chilling effect: "His mind was changing him."

"Oblivion" is composed in spare yet often poetic prose. More sympathetic in its portraitures than its satiric predecessors "Their Wildest Dreams" (2003) and "The Tutor" (2002), it's an artful variant of the familiar nightmare--familiar, indeed, as a fairy tale--of the amnesiac waking to a jigsaw-puzzle world to be reassembled by heroic effort. In its L.A.-noir atmosphere, as in its knottily woven plot, it may remind readers of Christopher Nolan's ingeniously contrived mystery film "Memento" (2000), whose initial violent scene is in fact its climax, from which, in reverse chronology, enigmatic vignettes follow as a man afflicted with anterograde amnesia tries to discover who has killed his wife. "Oblivion" similarly begins with a scene out of chronological order, in which Petrov commits perjury while testifying in a trial, though we don't understand this crucial fact until a hundred pages later, when, seeing himself on videotape, in the way of a man observing a stranger, Petrov understands it. The investigator may even be guilty of having murdered a former, blackmailing mistress, and of having disguised the killing as the last in a series committed by a madman ironically named Reasoner, whom Petrov was pursuing at the time: "Suppose there was a serial killer on the loose and you wanted to kill somebody. All you'd have to do is find out the details of the serial killings and do yours the very same way. Who would ever suspect?" Only another investigator, as it turns out.

Petrov is a riskily impaired hero for a work of genre fiction, a private "eye" whose vision is occluded. Before a cerebral hemorrhage wipes away much of his memory, he seems to have been a kind of machine of ratiocination. Following the example of his spymaster father, he takes all notes in code. He's a taxonomist of human emotion who has sketched and labelled ...