When they were preparing for the court-martial of Scott McDermott, the protagonist in "The Ants of God," an Air Force psychiatrist reported that he had been "distinctly antisocial before Vietnam made him homicidal as well." That report may have reflected his view of psychiatrists, bureaucrats, officers who take no personal risks and wars in which the goal is to avoid losing rather than to win. But it seems a bit harsh as a judgment of his total personality.

What McDermott did to get court-martialed was bomb an airfield in North Vietnam that had been declared off-limits. He did it because of clear-cut military necessity, without considering the political factors. Or perhaps without giving a damn about them. As the novel opens, McDermott has been drummed out of the Air Force and is a bush pilot in Ethiopia, smuggling weapons for the Anya-nya guerrillas and their Israeli advisers in the southern Sudan war. It is a smaller and less spectacular operation than Vietnam, and one that certainly has not attracted as much attention in this country. But some of the things to be learned from it are the same -- and, precisely because it is smaller and less complicated, because it involves American interests and emotions less intensely, it may be easier for us to learn from that war.

W. T. Tyler won considerable praise for his first novel, "The Man Who Lost the War," and "The Ants of God" should provoke more of the same. The name is the pseudonym of "a veteran American diplomat who has spent a decade abroad during his career, most recently in the Arab world," the publisher informs us. Less discreet sources have conjectured that he is James Akins, former ambassador to Saudi Arabia. Whoever he is (and it cannot be too deep a mystery; his photograph appears on the dust jacket), the book's background indicates that he must have spent some time in Ethiopia, particularly the southwest corner, near the border of the southern Sudan. Somewhere in his career, he has obviously developed a healthy contempt for manipulation, bureaucracy and the chain-of-command mentality.He embodies this contempt both in the character of McDermott and in the carefully elaborated plot of his novel.

At the center of "The ants of God" sits Samuel Eko, a Nuer tribesman from the southern Sudan who has moved to a village of his tribe in Ethiopia and works as a driver and handyman at a medical mission. He is on the sideline in the southern Sudan war, which is actually only the latest episode in what may be the longest war in history: the battle between Islam and other religions that has been waged intermittently in Ethiopia and the Sudan for more than 13 centuries. Although he does not contribute anything decisive to the plot of "The Ants of God," Samuel Eko is a character as fully realized as Scott McDermott and, like him, evidently a vehicle for some of the author's own views. He serves as a focal point, an index of what the book is all about, underneath the love triangle which is the mainspring of its plot and the guerrilla war that provides local color, suspence, hubbub and turmoil.

In the struggle between the Islamic, Arabic-speaking government in Khartoum and the Nilotic peoples of the south who speak tribal languages and worship tribal gods or the God of the Christians, Eko's loyalties are divided. The Arabs are his friends, the tribesmen his brothers. He grew up in Khartoum, speaks Arabic and among the people of his tribe he is "known for his independent ways and his Arabized manners." He has acquired the skills of a city-dweller -- for example, the ability to repair machines that are a mystery to country people -- but he has kept his tribal soul intact; he dresses in Arab-style clothing at work and in tribal style in the village. He talks regularly to a crocodile that lives in the Baro River near his village, and apparently the crocodile listens; at least when Eko tells it not to molest swimmers it goes away.

Midway through the book, Eko encounters a guerrilla captain he has known before and describes him with scorn: "He was a politician from the border. A coffeehouse politician. Now he has a gun. Does that make him a soldier?" Then the encounter moves him to philosophical reflections that bring the novel to the heart of the matter: "He is just an ant. They are all ants. They don't know what they are doing. Black or brown, Arab or Christian, Pagan or Catholic. To the eyes of God, if God has eyes, they are just all ants -- small, busy, crawling ants. Pieces of dust . . . So small that the differences between them don't matter."

This kind of statement announces the author's intent to produce more than a mere entertainment, although the surface of the story still deals with guerrilla war and McDermott's choice between two women: Penny Palmer, a young, pretty Californian who hides some depth beneath a spoiled-brat exterior, and Emily Farr, a middle-aged medical worker whose human warmth is buried under a set of principles as flinty as the soil of her native Vermont.

In the end, Tyler delivers on that promise and produces a book of substantial value, a book in which good guys and bad guys, lovers and haters, the sane and the insane, the fighters and the cowards and the manipulators and the sadists are all seen in the same perspective: ants, scurrying in patterns that are no less absorbing for their absurdity. It is expertly done and shows promise of even better things to come. It might be prudent to watch through another book or two before sending up rockets, but it is possible that we have here a new Graham Grenne or John le Carre.