IN THE ICONOLOGY of the Vietnam war, drugs oc-

cupy as significant a role as B-52s, napalm, free fire zones, and Charlie Cong. This may be an inescapable fact but it's a grave disadvantage for novelists, especially for those with pens loaded with purple ink: drug trips, hallucinogenic dreams, zonked-out introspections take the biscuit when it comes to boring reading. Try this:

"Thought winnowed down to a maundering thread. Frontal bone splintered into billowing motes of ivory dust, exposed neural lobes to the cool fall of descending air. Intimate fission flashed with the erratic tempo of summer lightning on a gray horizon. . . . He felt a hand move swiftly inward and seize the flaccid sponge of his mind within the grip of a velvet gloved fist. Silent static closed over consciousness."

Which is exactly what's happening to the mind of the reader. Passages like this pop up all through Mediations in Green to mar, though not critically, what is otherwise an uneven but on the whole impressive debut and addition to the canon of Vietnam war novels.

This novel (winner of the Maxwell Perkins Prize--an award bestowed by the publishers of the book themselves) charts in a series of sustained flashbacks the tour of duty of one Spec. 4 Griffin. We move to and fro in time between Vietnam and Griffin's drug-hazed present. These twin chronologies are demarcated also by a change in pronoun. The Vietnam sequences are in third-person omniscient narration; the present earns the subjective viewpoint of a narrative "I." The mix is further complicated by intersections of brief meditation (hence the book's title). In the postwar sequences Griffin (a lethargic junkie by now) is taken under the wing of a hip psychologist whose idea of therapy is to get his patient to embark on a series of meditations wherein he pretends he's a plant.

It has to be said that although these various sections with their pronoun changes and fractured chronology make the book seem more complicated and critically Ma la mode, they actually contribute little to the novel's impact and effect. Meditations in Green belongs to that category of Vietnam novel that includes If I Die in a Combat Zone (Tim O'Brien) and Close Quarters (Larry Heinemann): namely the thinly fictionalized memoir. It's a tradition with a long and respectable heritage, stretching back to, and beyond, Robert Graves' Goodbye to All That. In such books one is moved and appalled by their documentary truth--and Meditations is no exception. Its portrayal of the U.S. military machine and mind at their most brutally callous and complacent is a terrifying indictment.

But it's when one comes to consider this type of book's status as a work of fiction--as a product of the writer's imagination--that certain doubts are raised and certain needs unsatisfied. Documentary truth is some remove from imaginative vision, and it's in this last department that most war novels fail, and in which the whole genre of "war novel" is surprisingly deficient.

I would suggest that it was in an effort to provide this that the drugged-present sequences and the meditative interludes were supplied. One applauds the motive, but it seems to me that it is in the eyewitness testimony which Wright supplies that the novel is most admirable. It's a real bonus too that Griffin's job is ancillary to the main effort of the war. He examines reconnaissance photos, searching for traces of the elusive North Vietnam army, and later evaluating the defoliant effectiveness of Agent Orange.

The bizarre, peripheral nature of his unit's role in the war engenders its own absurdity. They sit around for long stretches of time, getting stoned, plotting revenge on their over-officious commander, counting the days till they go home. All the stupidity and chaotic mess of warfare are convincingly portrayed in the unit's squalid, apathetic life. But from time to time it seems that the novelist feels that this type of meaningless quiescence is insufficient and decides to go gung-ho. Consequently we get ambushed patrols, Griffin taking over from a wounded door gunner in a helicopter, Griffin volunterring for a dangerous mission and an apocalyptic attack on the base itself.

But why should this detract from the effectiveness of the novel? The answer is that it moves it into another category--the "war is hell" category. Since the great poets and novelists of the First World War, action sequences in war novels have been subject to the law of diminishing returns. One can only describe blood and guts all over the place in a limited number of ways and they have to be essayed with either a very specific motive in mind or with exceptional stylistic verve to succeed.

Wright, it's true, handles his action sequences very competently, but one example will have to suffice for the sort of dilemma he finds himself in. The sequence of the ambushed patrol seems to me to be one of the best subjective viewpoints of what it must be like to be under fire that I have read. The only trouble is that the person experiencing all this is a virginal, inept rookie out on his first patrol. As the rookie--one Claypool--sets off with immense trepidation all the clich,es of the war novel genre lead us to expect that he's going to run into danger. And sure enough he does. The fact that it's all brilliantly described is undermined by the extreme familiarity of the situation: an example of deficient imaginative vision consorting uneasily with impressive expert testimony.

Most war novels written by ex-combatants suffer from the same weaknesses. The urge to "tell it how it was" makes the necessary art and artifice required in writing a work of fiction all too apparent, and therefore unsuccessful. It's no surprise that the two best novels about the Vietnam war, are, on the one hand, the most fanciful and absurd (Going After Cacciato) and, on the other, the most removed (Dog Soldiers). Wright's novel-- flawed and impressive--makes a serious claim to join these two exemplars. But we're still waiting for the classic.