Hang a Left on Bob Hope : FUGITIVE NIGHTS, <i> By Joseph Wambaugh (Perigord/William Morrow: $22; 336 pp.)</i>

Since 1970, when his first novel, “The New Centurions,” was embraced by both critics and readers, Joseph Wambaugh, a former LAPD detective, has published 13 books--four of them nonfiction--that say, in essence, a policeman’s lot is not a happy one. Regardless of this somber theme, leading inevitably to a cast of characters plagued by depression, alcoholism, terminal cynicism and suicide, his novels have become increasingly more hilarious.

His newest, “Fugitive Nights,” which begins with a historic meeting of George Bush, former Japanese Prime Minister Toshiki Kaifu and the mayor of Palm Springs, Sonny Bono, is one of the funniest mysteries in years.

You could see it coming from as far back as 1975’s “The Choirboys,” when the author established a successful formula in which alienated, besotted policemen stagger through their thankless sleuthing with a sureness of purpose, all the while mouthing streetwise metaphors as unique as any Raymond Chandler imagined, and just as clever. It is to Wambaugh’s credit that as similar as are the structures of his recent fictions, each is surprisingly unique. Rather than repeating himself, he seems to be refining his technique and redefining his purpose.

His last novel, “The Big Orange,” arriving on the heels of a more-or-less straightforward work of crime journalism, “The Blooding,” was a wildly woozy piece following a bibulous ex-policeman named Winnie Farlow on a jaunty, jaundiced journey through the moneyed and privileged haunts of Newport Beach. “Fugitive” offers an equally besotted hero, Lynn Cutter, whose home base is Mayor Bono’s desert enclave.

Cutter is a smart-mouthed, spongy hulk who is counting the days until his disability pension allows him to spend days as well as nights in the Furnace Room, a neighborhood haunt that even he finds repulsive. Fate intervenes in the form of a beautiful but hardboiled ex-cop named Brenda Burrows, who has just opened a local private-detective agency and is in need of a police contact. She persuades Cutter, against his better judgment, to help her with a case.

The case involves, among other surprising people, an errant husband who is making secret deposits to a sperm bank. And if that isn’t antic enough, there’s a pathetically ambitious and hard-headed diminutive young police misfit named Nelson Hareem (a.k.a. “Dirty Hareem” and/or “Half-Nelson”) on the trail of a mysterious and probably murderous illegal alien. Hareem drags Cutter into that case, too.

Though a bit less critical of the desert than he was of Newport Beach, Wambaugh isn’t exactly singing “P.S. I Love You.” He writes, “Out-of-towners equated Palm Springs with glamour and money, and there was still a lot of it around. But the big money was relentlessly moving south in the valley, to Rancho Mirage, Palm Desert, Indian Wells, and even La Quinta now that PGA West was there. One didn’t find the Forbes Four Hundred bucks around the Las Palmas neighborhood any more, but there was still old quiet money. . . . It was in the downtown commercial section of Palm Springs that the big change showed, more than in the residential areas. Many of the shops were vacant now, even in season. There were signs in too many windows saying, ‘Moved to Palm Desert,’ to El Paseo, a shopping area with pretensions of becoming another Rodeo Drive.”

And there’s a bit of dialogue, describing the route for a proposed bike excursion, that says quite a lot about the town: “ ‘We’ll take it easy,’ Brenda said. ‘Maybe go up to Dinah Shore, out to Bob Hope, back on Gerald Ford. All the way to Frank Sinatra if you’re up to it.”

The novel does a bit of moving about, too. As it hopscotches from its erstwhile good guys--who are joined by a thoroughly professional but suicidal former cop named Jack Graves--to the deadly visitor closing in on his prey, its forward thrust is not unlike that of a shaggy-police-dog story. It isn’t suspense or even mystery that propels the reader. It’s a growing fondness for Cutter and his pals and a curiosity as to how all the various tendrils of the tale will be gathered.

Like Elmore Leonard, Wambaugh is much more interested in people than in the clean, neat ending and other similar conventions of the crime novel. And, considering the gags and sarcastic quips about politics, personalities and places, he’s obviously happier being a pundit than a plotter.

Readers should be just as happy. There are a number of tightly knit suspense thrillers on the market these days, and Lord knows, more than enough police procedurals. But how often do we see a novel that’s as slap-happy as it is savvy, where a dedicated assassin can be almost sidetracked by his first taste of Palm Springs affluence; where a dipso is nicknamed Ten-To-Six because he leans “to starboard from the waist up”; or where a hero, whose eyes look “like bags of plasma,” whose damaged knees have “all the flexibility of Margaret Thatcher,” confesses shamelessly to having “enough banking acumen to be George Bush’s son”? The man who pioneered the cop novel is not only finding life a great deal more humorous these days, he’s using his considerable skill to let us in on the joke, too.