AGENTS OF INNOCENCE By David Ignatius Norton. 444 pp. $17.95

HERE IS a rare example of spy fiction that, though fiction, tells the truth. In Agents of Innocence, David Ignatius is both historian and novelist: he assures us in an author's note that the book is a work of fiction and then provides a compelling account of how things fell apart in Lebanon between September of 1969 and April of 1983. Along the way Ignatius methodically, quietly and very entertainingly shows the reader how intelligence professionals really work. There is no over-heated prose, no car chases, no steamy sex, and above all, despite an environment of all-pervasive deceit, there are no villains. No one in Ignatius' account is precisely evil, though many are fools; people with jobs to do and beliefs to work for doggedly pursue goals that tear Lebanon apart. "For not to know we sinn'd is innocence," or so wrote Sir William Davenant in the 17th century, and though one or two figures here suffer from modest guilt feelings, the guilt is over a job not well done, a spouse neglected, rather than over the environment of deceit. In short, Ignatius has written a book that tells it as it is.

Tom Rogers arrives in Beirut, still a city that sparkles in the afternoon sun, one September day in 1969 with his wife, eight-year-old son and sick two-year-old daughter. We follow him to the end, as he rises in the CIA, quarrels gently with the Beirut station chief and less gently with Washington, and learns his way into the realities of Lebanese politics. What is one to do, he wonders, with a society where even the soccer league is divided along religious lines -- a Druse Moslem team, a Shiite Moslem team, two Sunni Moslem teams, three Maronite Christian teams, a Greek Orthodox team, two Armenian teams (one leftist and one rightest)? Carefully Rogers develops a penetration of Fatah, slowly he learns about the Bombmaker, who is teaching just about anyone who wants to learn how to make car bombs, for money and fun. Though he practices the deceit of his profession, Rogers also comes to the conclusion that most intelligence successes come from being open and straightforward. Along the way he meets young Arabs who fell in love with America in a time when America seemed pure, and he works with cynics who must believe in the universal absence of all innocence.

Rogers knows Arabic, and the Middle East, and human nature, and he is able to develop a relationship with a young Palestinian named Jamal Ramlawi who stands close to Yassar Arafat (who throughout the book is simply called the Old Man). Jamal is willing to provide information to Rogers but he refuses to think of himself as an agent of the Americans. Going by the book, the agency wants control over him, and a recruiter sent out from Washington makes a mess of it. Still, Rogers is able to stay in touch, and thus effectively has access to Arafat's chief of intelligence who, in turn, becomes a prime figure in Black September, the terrorist movement that takes its name from the expulsion of the PLO from Jordan by King Hussein in September, 1970. Israeli intelligence picks up hints of this relationship but leaves it alone until after the killing of Israeli athletes at the Munich Olympics, when Jamal is added to Mossad's revenge list.

FEW COULD tell this story so well as Ignatius has done. A diplomatic correspondent in the Middle East for The Wall Street Journal and now an associate editor of The Washington Post, Ignatius brings an unerring sense of balance to his account. He creates very real figures, Jewish, Lebanese, Palestinian, American, all in some measure sympathetic, all in some measure culpable, for the explosion that both begins and effectively ends the book. Once Ignatius looks as though he is going to slip, retailing an old British intelligence story about Mansfield Cumming, the legendary "C," and his wooden leg, and then, 20 pages later, he corrects himself, all with intent. The tradecraft is just right, the business of intelligence both understated and (as in the portrayal of Mossad's Yakov Levi, who must pass as a Frenchman) tense, and the sense of place, from the New Omayed Hotel in Damascus to the streets of Cairo is just right.

Ignatius is an effective writer because he does not raise his voice. Each sentence goes where he wishes it to. Operations are unfolded as though with the calm voice of historical fact, much as another writer of spy ficiton William Hood, hews close to the bone of reality in all of his work. Rendering a complex story deceptively simple, Ignatius draws in the reader who, utterly confused by the persistent destruction in Lebanon today, may have abandoned all hope of understanding the tragedy being played out in that beautiful land. This is a book for spy fans, certainly, for it tells a good story and tells it well, but it is equally a book for those who hate spy stories. It tells of blasphemous fables and dangerous deceits for the sturdy moralist who still holds to the innocence of hope.

Robin W. Winks, who teaches history at Yale, is the author of the recently published "Cloak & Gown: Scholars in the Secret War."