The Hot Ones : MAXIMUM BOB, <i> By Elmore Leonard (Delacorte: $20; 304 pp.)</i>

First, a necessary confession: I’m an Elmore Leonard fan.

That doesn’t mean I love everything he writes, and in fact for a while now I’ve been in mourning for the natural spin of the first novels--”Fifty-two Pickup,” “Unknown Man No. 89,” “Gold Coast” and “City Primeval”--that won him his high-flying reputation. But there’s pleasure in loyalty, so I hang in there and keep reading everything that comes down the pike, even if, lately, some of it’s seemed like Elmore Leonard imitating Elmore Leonard. And it’s paid off, because his new novel, “Maximum Bob,” is his best since the great early days.

Elmore Leonard once said, “I don’t write the weather.” He meant, I write story, I write people. “Maximum Bob” is a fine illustration. He grabs you and doesn’t let go. He delights you, he makes you see. You’re going for a ride into reality.

The setting is Palm Beach County, Florida, which in this instance doesn’t mean the dowagers on Worth Avenue, but rather the down-home crackers who populate the rest of the county stretching eastward from West Palm through the swamp as far as Lake Okeechobee--gator country. (At one point, amazingly, Leonard takes us into the mind of one of the beasts.)

It’s a world of folks who live in old frame houses with pickups and boat trailers sitting in the yard next to rusted washing machines and car parts; and killers like good ole boy Elvin Crowe, who wears $350 boots and a straw cowboy hat and has just served 10 years for cold-blooded murder, but it was the wrong man, Elvin explains, a little miffed that he did time at all. In this world, Jim Beam bourbon is the drug of choice: plenty of it.

It’s also the world of Judge Bob Gibbs of the Palm Beach County Circuit Court. “Hard time makes the boy a man” is the judge’s motto, and it earns him the nickname of Maximum Bob. Jail therapy is Bob’s simple solution to the world’s ills, but when he’s not stretching the outer edges of the sentencing envelope, he’s leching after just about any female under 40 who comes his way.

One of them--a mermaid at Weeki Wachee Spring, a nearby amusement park--he marries, but that turns sour when she is attacked by a roaming alligator and has an Experience: She’s invaded by what she calls her “discarnate entity,” a 12-year-old plantation slave girl who was killed by an alligator in 1855. The judge, at some point, decides to rid himself of his kooky wife and her alter ego, and that gets the story rolling.

At the same time he sets his carnal sights on a sexy 27-year-old Cuban-American probation officer named Kathy Baker, whose caseload includes enough psychotics to send any other sensitive young woman to either marriage or a nunnery. But Kathy is on a quest, and she becomes the hero of this dark tale.

Dark it is, because Leonard, like any true comic, has a melancholy view of the world and its primitive denizens. Without moralizing, he is telling us--no, he is showing us--how rotten life is in the heartland of the USA. In “Maximum Bob,” more than ever, he is the great delineator of the macho redneck, the professional thug, the semi-mindless street-wise slob who kills and maims and rapes because it’s part of the American mystique of violence and seems like fun, who periodically finds a home in prison so that he’s doing life-on-the-installment-plan, and is at the heart of the “crime problem” the rest of us discuss endlessly in the op-ed pages and at cocktail parties. But Leonard knows things the rest of us don’t, or at least he conjures them with such stunning imagination and sufficient editorial sense to create the aura of authenticity.

Do thrillers have any literary or social merit? Elmore Leonard’s prose, in its way, is as good as anything being written in this country. And anyone who is against stiff prison sentences and the death penalty has an obligation to read “Maximum Bob.”