BOOK REVIEW / NOVEL : From Potboiler Beginnings to Worthy Literary Thriller : THE RIVER SORROW <i> by Craig Holden</i> Delacorte Press $21.95, 378 pages

When Craig Holden found himself in financial straits a few years back, according to the publicity material that accompanies the pre-publication galleys of “The River Sorrow,” he resolved to write, under a pseudonym, a quick-money detective story.

He never finished the book: The cash crisis eased, and more significantly, the characters Holden invented for mercenary reasons began to take on lives of their own.

Conceived as a potboiler, “The River Sorrow” became a literary thriller--and a good one, as it turns out, for this is one first novel that’s quite likely to keep you up half the night.

The central figure is Dr. Adrian Lancaster, who lives in a small Michigan city, Morgantown, 90 miles west of Detroit. Lancaster is not, however, a stereotypical country doctor: He’s an emergency-room trauma specialist, for one thing, and a former heroin addict and small-time dealer, having been introduced to drugs while in medical school by his chemistry-whiz lover, Denise.

Lancaster is by no means at peace with himself--he still misses Denise, who disappeared after rescuing him from career-threatening drug charges--but Lancaster has at least begun to redeem the past: It was a delusion, he realizes, to think that running a high-class, sterile shooting gallery while in med school made him “a kind of capitalist Albert Schweitzer of the counterculture.”

He now devotes himself to saving lives, not only in the emergency room but also in a drug-treatment center where he volunteers.

The novel’s direction is obvious from the get-go--Lancaster will be forced to revisit a past he’d sooner forget, to rectify youthful mistakes, perhaps, or at least tie up loose ends.

He does so soon after witnessing in the emergency room what seems to be fall-out from a new drug war; a number of users and runners have suddenly come to grisly ends, their deaths linked to the reappearance of a very potent form of synthetic heroin known on the street as Fang.

Lancaster encounters many of the drug-culture bodies, barely living and thoroughly dead, early in “The River Sorrow,” and these passages are as compelling as they are bloody. (Holden knows the hospital environment well, having been a lab technician in a Toledo medical center.)

Lancaster tries to maintain the doctor’s clinical view of these violent deaths, but when he realizes that many of the corpses are connected to his addict days, he smells a setup. He panics and goes underground, hoping to unravel the mystery for himself.

Lancaster is an interesting and original figure, but the character who really stands out is Frank Brandon, the cop who initially hopes to nail him. Brandon has a chip on his shoulder, having been passed over for the police chief’s job and seen his family virtually destroyed in a Quaalude-induced car accident, but he knows when evidence adds up too neatly.

Brandon keeps his ideas to himself, however, not trusting either the sheriff’s department or the federal drug investigators who descend quickly--too quickly--on the various murder scenes.

His silence proves golden: There is indeed a conspiracy, one involving government officials, but Lancaster proves to be merely a bit player. Someone is trying to flush Detroit’s kingpin drug-pushers into the open, but who, and why?

Holden throws everything but the kitchen sink into “The River Sorrow,” from corrupt politicians, lawless federal agents and figures in mysterious disguises to snowmobile drug deals, high-speed shootouts and tape-recordings from the dead.

Although these tough-guy characters and spectacles can be a bit much, they never go over the top, so the novel generally retains its plausibility, up to and including the revelation of the identity of the evil genius behind the killings.

The disclosure comes as something of a surprise, but not entirely, because Holden has a way of making the unexpected seem inevitable. Doctors who use heroin? Cops who act with deliberation? Someone who devotes years to perfecting appropriate vengeance?

The potboiler origins of “The River Sorrow” are unmistakable, but Holden has transcended the genre with aplomb.