Novelist Gerald A. Browne sits on the edge of the sofa in his New York apartment, eyes darting, hands chopping the air. He has just finished describing the climactic chase scene atop St. Patrick's Cathedral in his current bestseller Stone 588 (Arbor House, $17.95). Browne is excited, hitting stride, his voice deeply resonant, his words as deft and clipped as his writing. In mid-breath his conversation shifts abruptly to the ending of his first big seller, his 1972 thriller, 11 Harrowhouse.

"It was done in the most hyper-dramatic, corny way you can think of," says Browne, 51. "It had the only set of lovers I've ever killed in a book. They're on a breakwater in Monte Carlo. She's about to take a nude swim. They embrace, and suddenly one bullet passes through her and into him, then another bullet from the other direction passes through his back and into her. So now they die, and he holds her. Her Viking red hair falls back. She looks up into his eyes and says, 'I'm afraid.' She has always been the brave one, never afraid. So he wants to tell her not to be, but he doesn't have to because they're already dead."

Silence. Face tightening, Browne still seems to be gazing at his crumpled lovers on the Monte Carlo quay. "I cared for them and I killed them. I did it," he says, eyes half-lidded. Merle, Browne's wife of 22 years, enters and places a bowl of strawberries on the coffee table. "Have some," she says matter-of-factly. "And remember, we have to get your coat cleaned, then go to the jeweler's." Merle, 42, a striking former fashion model, crosses the plush living room to answer the buzzing phone. "It's Cybill," Merle says and passes the receiver over the back of the sofa. "Hi, kid, what's up?" asks Browne, brightening. Actress Cybill Shepherd, Cosmopolitan editor Helen Gurley Brown, Arab billionaire Adnan Khashoggi and Browne's sprightly 80-year-old mother are a few who call him throughout the morning.

"I'm a giver, I love my friends," Browne later explains, adding that he has made many close ones through the success of his books and movie adaptations (11 Harrowhouse and another novel, Green Ice, have been filmed, and he's writing a screen version of 19 Purchase Street). "Writing is lonely, but I think everyone, whatever they do, crashes against insularity, aloneness. The only thing that makes it bearable is love. As a novelist, if I can help people realize this, fine."

Slapping his waistline bulge—"I always gain weight after writing a book, then have to work it off"—the 5' 7" author of 10 published novels notes that Stone 588, like most of his novels, fits into the "romantic thriller niche" of popular fiction. "I don't copy Robert Ludlum or Ken Follett," he says. "They don't do what I do. Hell, I'm an entertainer. I try for a certain elegant ambience, always with an avant theme—but not too avant." Adds Merle, now setting down a plate of grapes on the table: "There's passion in his books, and you learn so much."

Indeed, Stone 588 treats readers to a combination gem-heist caper and love story that takes place mostly in New York City's midtown diamond district. The book is also a virtual primer on gemology, the science of precious and semiprecious stones. As with Browne's other novels, a farfetched premise, this one involving a gem with the inventory label 588 and mysterious healing powers, becomes a credible possibility by story's end.

"I research a subject to death," Browne explains, holding a purple grape up to the light as if it were a Ceylonese amethyst. "Then I write for about nine months in longhand on yellow legal pads. When my stack of pads is about two and a half feet high, I know I'm almost finished." Browne, who has a 27-year-old daughter from a previous marriage, also maintains an apartment in Paris and a house in Connecticut, where he writes in a sparsely appointed room, facing a blank wall to avoid distractions.

Merle appears, wearing a blue promotion jacket with Stone 588 embla-zoned on the back. "Jeweler's, remember?" she says, retrieving the remaining strawberries and grapes. Later at Van Cleef & Arpels, jewelers to the superrich, Merle browses while Browne sits unnoticed in a corner. For Browne, who grew up the son of a woolen mill spinner in Hartford, Conn., it's a distant role and place from his "starving student-poet" days at UCLA, the University of New Mexico and the Sorbonne, long past his many jobs washing dishes, and 20 years after he quit a successful career as an advertising executive to write his first novel. The store manager spots the Stone 588 jacket, inquires, and Merle points to Browne. Soon the master of fictional stones is surrounded by his fans, gem lovers all. "I'm just a storyteller," he says, beaming, "but I'm nothing without an audience."