FROM THE CONTRASTING trim on the sleeve of his suit jacket to the heavy gold cufflinks to the status loafers, Sidney Sheldon's look spells S-U-C-C-E-S-S with a capital $. Which is borne out by the fact that, by offivial publication date of his new paperback reprint, Bloodline , and even before the promotion hype of the book began, some 2,950,000 copies were shipped, and they were selling like jelly beans at Easter. Bloodline was the number-one best seller in hardcover, and it looks as though history is about to repeat itself.

I put Mr. Sheldon at ease by telling him that, when I went into my supermarket, he had 20 top pockets out of 20 on the paperback rack there. When I left, he had 18 top pockets and two bottom ones and I had two top pockets. After all, it is my supermarket. He then puts me at ease by remarking that that seems perfectly fair to him. He's a relaxed, affable man, and he can afford to be. As the author of The Other Side of Midnight, Stranger in the Mirror, The Naked Face and Bloodline , he has carved out a market share for himself comparable in its way to Exxon's. And he didn't start from aquare one, either.... When he was 25, he had three hit musicals running on Broadway at the same time. He created the television hits I Dream of Jeannie and The Patty Duke Show , and he wrote the screenplays for the films Easter Parade, Annie Get Your Gun, The Bachelor and The Bobby Soxer , among others. He's also worked in a factory, as an usher, as a barker, sold shoes, been a hang-boy (you give your coat to a pretty checkroom girl and she gives it to a boy to do the hanging); went to Hollywood when he was 17.

"I've been lucky," says Sheldon. "I got into books at the right time, about 10 years ago, and I got in by accident. It had never occurred to me to write a novel.I had done 250 television scripts just for shows of mine that I had created, 30 motion pictures (some of which I produced and directed), eight Broadway plays. I had an idea, and I wanted to get into the characters' heads, and the only way I could do it was as a novel. So, mornings, I would call in one of my secretaries and dictate --" He is interrupted by the low, savage growl issuing from the jealous interviewer's throat, and instantly takes the defense. "Don't forget I was running a big company, Sidney Sheldon Productions. Our budget for the year was many millions of dollars. I owned the company." The interviewer decides not to spring, and Sheldon continues.

"From 9 to 12 I'd dictate; then I'd put on my other hat, that of producer of movies, TV, whatever. When the book came out (The Naked Face ) I think we sold three copies; my wife bought one, my mother bought one, and I bought one. [Actually, although Sheldon's editor, Hillel Black of William Morrow, still maintains that two of those were returned to the store, Face sold a respectable 15,000 in hardcover and more than 2 million in paperback since the success of Midnight .] I made no money on the book; I lost money because I publicized it myself. But I had such fun writing it. It was fun not having anyone second-guess me, not having actors tell me about lines they couldn't read. So I sat down to write another book, with no idea that it would be any more successful than The Naked Face . This book was, of course, The Other Side of Midnight , and it changed my whole life.

"It takes me a year to write a book, to research and write it. I've just finished dictating the draft of my new novel. Now I'm going all around the world for two months. When I get home, I'll go back to page one and start again. In one year, I will do up to 12 complete re-writes on a book, until I feel it's ready to give to the publisher. At that point, I don't hand it over, but go back and cut, arbitrarily, 10 percent of the book, 10 out of every 100 pages, to make it read much faster. I'm a perfectionist, and I try to make it as good as I can. I deliberately try for that can't-put-it-down effect, Perils of Pauline time.

"I read a lot, three to five books a week. I read everything, from George Bernard Shaw to Irving Wallace. I just finished Overload , Puzo, you name it. I pile books around my bed, the 'urgent' books; it drives my wife crazy. On the way to Australia from London, Jorja and I are stopping in Singapore for a week, where I'll do research. When I write about a restaurant, I've been there, and I've eaten the meal I describe. For The Other Side of Midnight , I met Onassis pilot, met with lawyers and went through the prisons of Greece. For my next book, which is about a criminal attorney, I'm meeting with the district attorney here. I'll be visiting correctional facilities; I'm going to spend time at Riker's Island. I have to see those cells, smell them, see the people in them. There's a scene in Bloodline where the heroine is going down a mountain road in Sardinia in a jeep, and she has no brakes. She knows she's going to die. I got a car and I went down that mountain road; my wife Jorja was terrified. When I got to the bottom of the mountain, I knew how I was going to write that scene."

"You had brakes?" I asked.

"I had brakes, but I went as fast as I could.

"The only thing about this kind of success that bothers me is that it's being in front of the camera, as it were. I've always been behind it. I produced and directed a picture with Cary Grant, Dream Wife . And people would come up to Cary and say, I loved your picture. They'd come up to Barbara Eden and say, I love I Dream of Jeannie , which I created and wrote and produced. And I understand that, and I've always felt that it was appropriate. Now, for the first time, writing novels, I find that I'm the star. Only because, if people like my novels, they don't write to the publisher and say, you printed that beautifully. There's no Barbara Eden, Cary Grant or Warren Beatty. There's just me."