Updated July 11, 1988 12:00 PM

When Francine Pascal introduced the identical twin heroines of her teen novel series Sweet Valley High five years ago, she modestly announced that they were “the most adorable, dazzling 16-year-old girls imaginable.” Right from the start it was as clear as their unblemished complexions that Elizabeth and Jessica Wakefield would not be your garden-variety adolescents. No braces or gangly legs for them, no Clearasil, no anguished moments spent studying themselves in the mirror. True, it turned out that beneath their dazzle the twins were as different as girls who wear matching gold lavalieres can possibly be. Elizabeth was “friendly, outgoing and sincere”; Jessica was “snobbish and conniving.” Around these polar-opposite twins revolved a whole world of familiar teenage problems, and upon them Pascal has built an empire.

In perpetual attendance at mythical Sweet Valley High, the Wakefields are forever the most popular girls in school. In fact, they may be the most popular girls of all time in teen fiction. Unlike such sleuthing predecessors as Nancy Drew and the Hardy Boys, Elizabeth and Jessica help friends solve figure flaws, not crimes, and they’re after cute guys, not bad guys. Since making their debut in Double Love, in which they fought over “tall, lean” Todd Wilkins, the good and bad twins have appeared in 45 Sweet Valley High books (for girls 12 and up) and in 19 more of the Sweet Valley Twins series, a spinoff for preteens. In that time, pubescent goings-on in the idyllic, overwhelmingly white, upper-middle-class suburb of Sweet Valley, Calif., have produced enough revenue to move the whole population to Beverly Hills. With more than 40 million books in print in the U.S. alone (they have also been translated into 15 languages), the Sweet Valley series is a publishing phenomenon. It made history in 1985 when Perfect Summer(about a romantic bike trip) became the first young-adult novel ever to make the New York Times paperback best-seller list.

The twins’ little empire will expand even more should NBC launch a projected TV series early in 1989. (Pascal’s daughter, NBC producer Jamie Stewart Carmen, is conducting a nationwide search for a perfect set of identical twins.)

As every good story should, however, this one has a twist, and it involves the twins’ creator. A 50-plus blond who churns out a book a month to meet a 100-novel, multimillion-dollar contract with Bantam Books, Pascal admits there’s a ghost in her closet. An energetic woman with a passion for marketing and sales, she doesn’t actually write all those books, she only “conceives” them. They are set to words by hired pens working from Pascal’s series’ “bible”—a long, detailed guide spelling out the themes, characters and settings—and her plot outline. She worked out this methodology for the very first Sweet Valley book and has stayed with it ever since.

Pascal can write, when she has to. She is the author of two adult works (Save Johanna!, a novel concerning the self-destruction of a writer, and the nonfiction book The Strange Case of Patty Hearst), as well as several acclaimed teen novels(including Love and Betrayal & Hold the Mayo). But Pascal says that it’s taxing enough for her to write one Sweet Valley outline a month, thank you; composing all 100-plus books planned for the series would be a feat to addle the mind. Besides, she insists, she never works simply by formula. “If I don’t choke up at the end of an outline, it’s no good, and I go back to the typewriter,” she says. “It’s really got to get you right there,” she adds, indicating her heart. “It” almost always gets readers, too. Pascal receives up to 1,000 letters a month from young fans, many of whom say that she got them hooked on books. To critics who accuse her of grinding out junk food for kids starved for nourishing reading, Pascal argues, “These books have uncovered a whole population of young girls who were never reading. I don’t know that they’re all going to go on to War and Peace, but we have created readers out of nonreaders. If they go on to Harlequin romances, so what? They’re going to read.”

Pascal is convinced that, potentially anyway, Sweet Valley could go on forever. “No matter when you were born or where, puberty is the same,” she says. “It’s the same for your parents as it is for you—what’s happening in your body dictates everything. Sweet Valley is the essence of high school. The world outside is just an adult shadow going by. The parents barely exist. Action takes place in bedrooms, cars and school. It’s that moment before reality hits, when you really do believe in the romantic values—sacrifice, love, loyalty, friendship—before you get jaded and slip off into adulthood.”

Born Francine Rubin in Manhattan and raised in Queens, Pascal was inspired to write not by her late father, an auctioneer, nor her mother, who now lives in Florida, but by her late brother, Michael Stewart, who worked on Sid Caesar’s Your Show of Shows and wrote the books for such Broadway hits as Bye Bye Birdie, Hello, Dolly!, George M! and 42nd Street. She met her future husband, John Pascal, at New York University, where both were students. They married in 1964 and raised her three daughters from an earlier marriage while John worked his way up to columnist on the Long Island newspaper Newsday. The year they wed, Francine and John teamed up as “second writers” on the TV soap The Young Marrieds—her first experience in group writing. They went on to collaborate on George M! in 1968, and in 1974 they jointly knocked out the Patty Hearst book in 29 days. Pascal became a novelist “one day in 1975, when I had a revelation. I said, ‘John, what if—my two favorite words—’a 13-year-old girl who can’t get along with her mother goes back in time to her mother’s childhood and becomes her best friend?’ I just loved the idea so much. So I sat down and wrote it.” Han-gin’ Out with Cici (later made into an ABC special) became a hit in the lucrative young-adult market, and Pascal began turning out a new novel each year.

She was working on Love and Betrayal when her husband died, at 48, of lung cancer in 1981. Pascal still chokes up when she speaks of him. “John was a lovely man, a wonderful father, a beautiful writer,” she says. “He was my mentor. They still have an award in his name at Newsday. He is just sensational. After his death I spent eight months alone in France, and that kept me so busy I didn’t have time to indulge the grief. Then I came home, strong and healthy, and fell apart. The demons were waiting for me. When you write, you have to get back into your mind, and that was the one place that was a little dangerous.”

Ultimately, though, it was writing that rescued her. Struggling to finish Love and Betrayal in 1982, she recalled an old idea of hers for a TV soap about teens, and an editor friend suggested that she try it in book form. “I said, ‘Gee, that’s a very interesting idea.’ I took two days out and began to think how it would work. I came up with these two wonderful characters, a sort of Jekyll and Hyde. Once I started, I began to really love it all.”

Six years later, Pascal is at work plotting her 55th book in the Sweet Valley High series and her 28th with the Sweet Valley Twins. She is also writing a script for the NBC pilot and helping daughter Jamie in the Great American Twin search. She admits that she has a “career problem,” though it’s one that most writers might envy. “It’s gotten so enormous, it’s an industry,” she says. “I want to be able to write other things now.” She is co-authoring a novel about the celebrity-packed Dakota apartment building in New York, and she would also like to write the story of a love affair based on her marriage.

All of which leaves precious little time for a nonfiction love life. Pascal lives alone in the sprawling co-op she and her late husband shared. Memories haunt her still, and new love does not bloom as easily as it does in Sweet Valley, but the ground for it now seems to be prepared. “I can always make room for romance,” she says, “but at the moment I’m uninvolved. Of course,” she adds slyly, “there are a number of men in my life—Bruce Pat-man, Todd Wilkins, Ken Mathews.” But those are all Sweet Valley boys, and Pascal is, in fact, beginning to date. “After all,” she says, “I’m not pinned.”