Ian Rankin has said that when he was writing his first John Rebus mystery, he was trying to fashion a modern-day "Dr. Jekyll and Mr. Hyde."

	"FLESHMARKET ALLEY" Ian Rankin Little, Brown ($22.95)

Edinburgh, home to Robert Louis Stevenson, is also Rankin's home, and all the Rebus books are set there. It's no coincidence, then, that the city as Rankin describes it is draped in Gothic shadows.

The Gothic element ebbs and flows depending on the book -- several have dug into local lore of grave robbers and witchery, although the culprits have turned out to be merely bad flesh and blood. One of his best, "Set in Darkness, involved the discovery of human remains in Edinburgh's ancient cellars and tunnels.

"Fleshmarket Alley," the 15th full-length Rebus novel, appears to start the same way, but Rankin is playing off our expectations -- the skeletons of a woman and child buried in concrete beneath The Warlock pub in Fleshmarket Alley turn out to be fakes, perhaps a publicity stunt by the owner, who wants to make his watering hole a stop on the city's "ghost tours."

At the same time, a dismal housing project called Knoxland has yielded up a genuine corpse -- a Kurdish journalist and asylum-seeker.

Detective Inspector Rebus and his colleague, Detective Sergeant Siobhan Clarke, go slogging after clues to both puzzles, and a third to boot -- the disappearance of a teenage girl whose sister had committed suicide after she was raped.

Any fan of Rankin will know straight off that these seemingly unrelated incidents intersect. The joy, because Rankin constructs his plots so neatly, is in seeing how. The investigation takes Rebus and Clarke from the housing project to Whitemire, a detention center for illegal immigrants, from beaten-down coal-mining suburbs to the city's red-light district.

Rankin is intensely interested in Scottish psychology and sociology, and his cops, barmen, barristers, hairstylists, taxi drivers and stone-cold killers usually ring true, in part due to terse, dead-on dialogue.

As for Rebus himself, he's an antihero whose mixture of doggedness and pigheadedness is endearing. Past 50, he's being eased into retirement.

He drinks, he smokes, and he spends a lot of time with himself and the ghosts of his past. He shoots off his mouth, and he disobeys orders. He's also a loyal friend to Clarke and harbors a soft spot for victims of crime and of an uncaring society.

You could call some of these traits noir cliches; when tweaked by a writer as artful as Rankin, they satisfy some deep, archetypal yearning.

There are a few places, however, where "Fleshmarket Alley" doesn't finesse the conventions so well; for instance, Rebus' flirtation with a lefty activist is mostly cardboard. What's more, the book never pencils in Rebus' personality with as much telling detail or produces quite as potent a frisson of terror and fate as, say, "A Question of Blood" or "Black and Blue."

Nevertheless, this book is a solid addition to Rankin's work. The essence of Rebus comes through -- how joy wells up in his heart when he sniffs the wind, gets on a bad guy's trail and doesn't quit until his teeth are around his leg.

Toward the end, Rebus is chasing a much younger, fitter crook through a tunnel and up to the street, where the bad guy is collared by a waiting cop. As the perp is being led away, a panting Rebus gets in his face and says, "I was gaining. Honest."