The Ross Thomas tour of Los Angeles is not for the faint of heart or soft of buttock. The tour takes the better part of a day, most of it spent in the cramped confines of Thomas' Honda Prelude, as its 61-year-old driver pays rather more attention to the sites he's pointing out than to the vagaries of L.A. traffic. Yet whether he is cruising by the Santa Monica apartment building where Raymond Chandler once lived, indicating the thatch-roofed Hansel-and-Gretel house in Beverly Hills or looking in vain for the canals of Venice, Thomas' comments are so wonderfully wry that fear and fatigue are soon forgotten. He gestures toward a Chinese restaurant on Santa Monica Boulevard that serves "the worst food in L.A." Then he swings over to a splendidly seedy section of Pico Boulevard of which he is especially fond. There, for the briefest of moments before returning to the freeway, his eye is caught by a sign that reads Make-Believe, Inc.

As one of America's foremost practitioners of political thrillers, Thomas has been manning his own branch of Make-Believe, Inc. for 21 years now. Twentieth-Century Crime and Mystery Writers describes him as "America's answer to Len Deighton and John le Carré, except that he is funnier than either." Last month Thomas published his 21st novel, Out on the Rim, a labyrinthine tale of double-crossing con artists, set in the Philippines, that may become his first national best-seller.

Thomas wrote his first novel in just two months in 1965. "Since I didn't know what I was doing," he says blithely, "it came easily." He mailed the manuscript off to a publisher recommended by a friend, and it was accepted. Called The Cold War Swap, it won the 1966 Edgar (mystery writing's equivalent of an Oscar) for best first novel of the year. "All of a sudden," Thomas remembers, "I had a new identity: novelist. I figure that saved me about $200,000 worth of psychiatry." With a brief foray into screenwriting—he once likened moviemaking to group therapy "or perhaps group sex, which can be rather disappointing too, for all I know"—Thomas has averaged a book a year since his debut. In 1984 he won another Edgar for Briarpatch, which was voted best novel of the year.

Briarpatch is set in an unnamed Western metropolis, but one that is clearly modeled on Thomas' native Oklahoma City. The son of a building contractor, Thomas won a short story contest his senior year in high school. The prize, if he remembers correctly, was "five bucks and a scroll." After graduating in 1943, Thomas spent two years as an infantryman and served in the Philippines, an experience that provided background for Out on the Rim. Many of Thomas' novels are informed by previous occupations: public relations man, newspaper reporter and consultant for LBJ's War on Poverty. "I try to peg every book on a ledge of actual experience," says the author.

Thomas now spends four or five hours a day writing. "This is what I do," he says matter-of-factly. "It's no chore to sit down every morning." If he experiences a bout of writer's block, he will hop in the car and "drive over to the Valley and go to a picture show," he says. "I eat buckets of popcorn—the height of wickedness."

It is a quiet life. "I went to one of my four dinner parties a year the other day," says Thomas, a self-described "boring recluse." He stopped drinking 10 years ago and quit smoking three years ago. Now he self-consciously pops a piece of nicotine-flavored gum into his mouth every few minutes. Thomas, who was divorced from his first wife in 1961, has no children. He and his 53-year-old second wife, Rosalie, live with two cats in a modest house in the Malibu hills. Thomas proudly reports that Rosalie was president of the local Democratic Club for two years and notes that his primary function as "the Denis Thatcher of Malibu" was to "move the chairs in and out of the living room."

An admitted political junkie, Thomas calls last summer "my best since Watergate" because he was able to get up at 6:30 in the morning to watch the Iran-contra hearings. An unrepentant liberal and cynic, he feels both qualities are useful in life and in writing. "You have to have a certain amount of cynicism to survive," he says, "but you also have to have a certain amount of compassion to live with yourself."

Poised on the brink of the literary big time, Thomas can be heartened by the example of Elmore Leonard. Like Thomas, Leonard was a mild-mannered, middle-aged suspense writer who had been toiling in semi-obscurity for more than two decades. Then, several years ago, he inexplicably burst into the nation's literary consciousness. Who knows? Perhaps this is Ross Thomas' year to come in from out on the rim. After all, he's got all the qualifications—and his middle name, it turns out, is Elmore.