By William D. Pease

Viking. 354 pp. $19.95

This exceptionally complicated and exceptionally entertaining first novel is the work of a writer who knows whereof he writes, which in this case happens to be drug dealing and official corruption in the District of Columbia. William D. Pease had 18 years as a prosecutor in Washington, both city and federal, and tried many notable cases, among them the successful one against Mayor Barry's former wife, Mary Treadwell, and four codefendants. Now he is on the other side of the fence, defending persons charged with white-collar federal offenses.

On the evidence of "Playing the Dozens," though, it's hard to doubt that Pease's sympathies still lie with the men and women in the police station and the district attorney's office. The central figure in the novel, Michael Holden, is an assistant U.S. attorney -- like Pease, he has 15 years in the job, and like Pease he leaves it in the end -- and the other most sympathetic characters are two detectives on the District police force; it's a novel about how crooks get caught, and though Pease has no illusions about anyone involved in the process, he clearly likes to see justice done and he doesn't object to a touch of retribution in the process.

His story begins, as so many such stories do, with what seems to be an isolated incident: When a District policeman enters a bar, a brooding man spins in his chair and with no preamble shoots the policeman dead. But in jail, under intense questioning by Holden and the two detectives, Eddie Nickles and Jimmy Legget, the murderer begins to spill out bits and pieces of information that seem to point, however uncertainly, toward a wealthy funeral director, Milton Higgs, commonly known if never proved to be involved in drug dealing and unseemly political connections.

Higgs scarcely says a word or makes a gesture in the novel, but he is the ominous presence that hangs over every page of it. When a trusted member of his inner circle at last comes to the law, she tells Holden:

"This man has an almost childlike fascination with being what he is. It's a big game to him. A dangerous and very profitable game, but it's still a game. He has people followed just for the excitement of knowing things about them. ... Years ago he set someone up for a reason. He needed some stock or something. And when it worked out so well he just kept doing it. Probably fewer than ten per cent of the people he has on tapes even know it. They may never know it. He just likes having it. Don't underestimate how dangerous he can be."

If anything, that itself is an understatement. Higgs's hands are everywhere, and never to socially redeeming purpose. He sets up apartments, hires an apostate FBI man to wire them, and catches prominent people in government and the police force in compromising sexual situations; he uses the information thus gained not for money but to gain influence over those in power. He also seems to have a spy in the district attorney's office, since he and his operatives know what the prosecutors and cops are doing and thinking just about as soon as they've done and thought it.

He seems to be impregnable; a couple of years before Holden and his staff constructed an airtight case leading up through various city offices to that of the mayor himself and involving Higgs at nearly every step along the way, but suddenly the rug was pulled out from under them by the DA himself. The result was to leave Holden deeply embittered over what he believed to be betrayal and ever more determined to bring Higgs down, even as he acknowledges the steep odds against doing so.

His campaign -- and "campaign" really is the word for it -- leads the novel in a startling number of directions, among them elaborately laundered bank accounts, a heroin deal of staggering proportions and various more personal intrigues. There is of course a woman, who not surprisingly finds it no great treat to be in love with a man whose work so consumes him; whether she will have to pay a price for their relationship, and if so what that price will be, is the novel's principal subplot.

Pease handles this and other such matters competently but not with much dexterity. He's a lawyer more than a novelist, which shows not merely in some stock characters -- the boozy old detective who gains new interest in his work, the green young detective learning the ropes, not to mention innumerable unsavory villains -- but also in an occasional inability to fool the reader; I guessed the identity of the mole in the DA's office on Page 152, and I was right.

But the shortcomings of "Playing the Dozens," such as they are, are far outweighed by its strengths. As a guide to how the dirty business of big-money drug dealing is done, it has the clear air of authenticity. As an account of how work spills over into private life and threatens its tranquillity, it is accurate and cautionary. And for most readers perhaps most important of all, as a suspense story it absolutely fills the bill; you may know who the mole is but you won't know much else, and Pease keeps you on edge right up to the novel's noisy climax and witty denouement.

All of which is to say that "Playing the Dozens" is a serious and instructive piece of popular fiction. You can learn from it and you can have a good time with it; that's a combination that many American readers find irresistible.