THERE ARE A number of excellent reasons why James Jone's last novel shouldn't work, none of them particularly new. Jones was neither a psychologist nor a stylist; his characterizations lack both depth and complexity and his prose is serviceable at best, although there is, as always, rather a lot of it. His notions about sex are frequently preposterous, and his ideas concerning American womanhood are egregious when they are not positively insulting. His protagonists are unpleasant. His plot is a symphony based on a single note.His earnestness resembles that a man trying to thread a needle in boxing gloves.

These qualitites have inevitably proven fatal to most if not all of Jone's civilian fiction, but in Whistle - as in its predecessors in the trilogy, From Here to Eternity and The Thin Red Line - they are either moot or, what is more remarkable, they are improbably transmuted into virtues. What his characters lack in depth is more than made up for in resonance. The interminable clumsiness of the prose, the sexual naivete, and the unidimensional eroticism of the male-female relationships cease to function as crippling liabilities and become instead badges of authenticity.

Jones as a writer had mastered a single subject: World War II as perceived and experienced by the proletariat of the military slum, the common professional soldiery. If this words do not possess the suppleness, wit, and majesty brought to that struggle by enthusiastic amateurs, they also lack the innocence; Jones, like his protagonists, worships in a different church. Born losers with the intellectual delicacy of migrant ditch-diggers, they are utterly ordinary men in an absolutely extraordinary situation, their fantasies are cheap, and their only loyalty is to each other and the units in which they serve. Their dilemma is not a subtle one, but it is gigantic. They are doing the only job they have ever been trained to do, and it is driving them mad. With its peculiar crude power, James Jone's voice is the best and truest one they will ever have.

Combat, by its very absence, dominates every page of Whistle and every moment of the lives of the men within it. We have met three of them before, in other books and under different names. First Sergeant Mart Winch is Welsh of The Thin Red Line and Warden of From Here to Eternity . Mess Sergeant Johnny Strange appeared as Storm and Stark, and Corporal Bobby Prell - Jones's perfect soldier who exists only to kill and be killed, time and again as in a hall of mirrors - was Private Witt and, most memorably, Prewitt, the doomed bugler of Schofield Barracks. The fourth and least successfullly realized member of the quartet is a newcomer, Sergeant Landers, a middle-class draftee whose goals have been understandably muddled by the circumstance of combat but whose previous life Jones, perhaps equally understandably, has a hard time imagining.

Separately wounded in the New Britain campaign, they are reunited at an Army hospital outside the city of Luxor, a classic liberty town that is part Memphis and part Nashville. Although, as they regain their strength, Jones rewards them with an old soldiers' notion of paradise on Earth - rivers of booze, endless partying, soft billets, and countless pliable girls of surpassing beauty - each finds himself impaled on the horns of a dilemma as old as myth and warfare, and each is unhinged by it. Like Theseus, they have been robbed of their deaths. Separated by half a world from their disintegrating platoons, eking out a gaudy half-life that makes a mockery of the enduring torment of their troops, unable to bear either present comfort or a repetition of the experience, they perish as a kind of inconclusive afterthought, destroying themselves in fugue. Winch goes mad; the others choose suicide.

Jones at his best - and he is at his best here - was neither a cynic nor a romantic; he possessed none of Hemingway's power of self-delusion. It is tempting to extract a facile metaphor of the human condition from his vision of battle, but he will not allow us to do so. His integrity would not permit him to treat combat as a bad roll of the dice; it is an unendurable proposition for which no preparation is adequate, a situation unspeakable in its horrors. Completed from Jone's outline by his friend Willie Morris, this is an important book, and it completes a monument that is certain to endure. It may very well be the only major body of American fiction to come out of the war. If, as Mallarme would have it, the novelist is a mirror walking down the road of man, James Jones accepted the challenge, and in the last analysis he proved more than equal to the task.