BOOK REVIEW / Bitter Wolff in sheep's clothing: In Pharaoh's Army - Tobias Wolff: Bloomsbury, pounds 12.99

Talk about getting out of the frying pan and into the fire. Tobias Wolff joined the army because he thought it would be safer than ships. As an 18-year-old, he was working on a survey vessel in the North Atlantic when, one day, a red-haired mechanic tried to kill him. Wolff was sleeping with his head on an idle propeller; he heard a noise, woke with a start, and sat up just before the silver blades roared into life. They would have minced his head. He weighed up his chances of surviving a renewed assault, figured they were small, and signed up for the army on the grounds that most of the writers he admired - Mailer, Remarque, Hemingway - had at one time been soldiers.

He loved the military training and was good at it. But he received a sombre warning that the real thing might not be quite so fine when he read in the paper that his best friend, an audacious cheermonger called Hugh, had been killed. Then he arrived in Vietnam himself. As a Vietnamese speaker, he was ostensibly in a relatively exalted position, but his tour of duty, as represented by these highlights, seems to have consisted mainly of scrounging television sets, trading in rifles and war souvenirs, and waiting for bad luck to arrive. There was plenty of it about.

The book is only incidentally a portrait of the war, which is perhaps just as well: there is no shortage of those. But Wolff is a high, clear writer - one of the best - and this is, in effect, volume two of the autobiography he began in This Boy's Life. Even under fire, Wolff was self-consciously having an experience, giving himself something to write about one day. And quite a large part of what is only a small book is taken up with memories of the author's father, an ex-convict whose indisciplined life fostered in Wolff the desire for order. So far as combat goes, we are offered, in clean and suggestive lines, a choice sequence of pregnant incidents.

The story begins with Wolff driving his armour-plated truck hard over a group of bicycles, too frightened to stop, sending Vietnamese peasants leaping from beneath the wheels. It ends with a recollection of Hugh shouting above the din - Are we having fun? - and leaping from the plane.

And it is held together by a strand of outrageous sentimentality - Wolff rescues a puppy from a barbecue by bribing the soldier who planned to cook it, and looks after it. As a farewell jest, he is given the dog in a stew - ah, these soldierly gags - at his going-home party. He is shocked, but stoic. 'There was only one way left to do him justice. I bent to my plate and polished him off.'

Wolff takes time out to recall an intemperate and unsuccessful love affair with Vera, back home in Washington. But the most striking relationship in the book is the one between Wolff, a lieutenant, and an extremely capable black sergeant called Benet on whom he leans thoroughly. Wolff is painfully aware of the precarious, official nature of their relationship. 'He called me Sir. He found work for us when there didn't seem to be any and somehow let me know what orders I should give him to preserve the fiction of my authority. I knew that he was my superior in every way that mattered, but he didn't allow me to acknowledge this and gave no sign of suspecting it himself. If he had, our barely sufficient imitation of purposeful existence would have collapsed.'

At moments such as this, Wolff almost leaves himself open to the charge that he is too self-deprecating, that the pathos on offer in these buddyish apologies comes too easily, or that he is only confessing to things he is secretly proud of, such as unusual sensitivity. But he has taken a lot of trouble not to be merely self-piteous. He does not attempt to monitor the sad comedy of life under fire - that would probably strike him as trite; instead he refines a strain of strong and tender irony. He developed, he tells us, a special look to deter the snipers he felt sure, most of the time, had his head in their sights. 'I prepared a face for the sniper to judge - not a brave or confident face, but not a fearful one either. What I tried to do was look well-meaning and slightly apologetic, like a very nice person who has been swept up by forces beyond his control and set down in a place where he knows he doesn't belong and that he intends to vacate the first chance he gets.'

He is happy, thank goodness, to extend this knowing asperity to others. Late on in his tour he finds himself working for, and hating, a noisy officer called Captain Kale. 'Captain Kale,' he tells us, 'owned records of people playing accordions, and could tell the difference between them.' Kale also orders Bavarian souvenirs from a mail-order company in Singapore, and has picked out a stash of cuckoo clocks, furniture made from antlers, figurines in lederhosen, and bits of folk art. 'He intended to furnish his house with these goods,' we learn. 'He'd seen them, he said, and there was no way you could tell they weren't German.'

Wolff lets us know that he doesn't think much of this; but doesn't mind admitting that it is not the worst of madnesses. 'We were advisers,' he says, 'but we didn't know exactly what advice we were supposed to be giving, or to whom.' In Pharaoh's Army is extremely unlike Michael Herr's celebrated Despatches, a high-octane, hallucinogenic ramble through the war-struck paddy fields. But in its quiet manner it is circling the same profound puzzles, the same drastic doubts. Wolff is in Vietnam for the Tet offensive, and he recalls the murderous mood that came upon Americans in its aftermath: 'The VC came into My Tho knowing what would happen. They knew that once they were among the people we would abandon our pretence of distinguishing between them. We would kill them all to get at one. In this way they taught the people that we did not love them and would not protect them; that for all our talk of partnership and brotherhood we disliked and mistrusted them, and that we would kill every last one of them to save our own skins.' The personal is political, even in war. Especially in war.

So much of the life-and-death part was just luck, though. Wolff explains how swiftly the military certainties dissolved. 'Despite the promise implicit in our training - If you do everything right, you'll make it home - you couldn't help but notice that the good troops were getting killed right along with the slackers and shitbirds.' He describes his close calls - a hand grenade under his truck that by some miracle didn't explode, a howitzer that fell from a helicopter, a fateful hand that fell on another man's shoulder - and winces. There just isn't a way to make them mean anything, apart from that he was lucky, and the others weren't.

At the end Wolff returns, first to California, then to Washington and finally to Oxford, England. He bumps into a few peaceniks at Berkeley who are declaring 'unconditional war' on the government and is momentarily hysterical with anger before fleeing, his face burning with embarrassment (he had come to enrol as a student). Even those whose sympathies lie entirely with the protesters needn't feel bad about blushing with the author here. Like they say: it shouldn't happen to a vet.