Francine Pascal, a former soap-opera scriptwriter from Queens who conjured up an entire literary universe among the blue-eyed cheerleaders and square-jawed jocks of suburban Los Angeles, most notably in her long-running and mega-best-selling “Sweet Valley High” series of young-adult novels, died on Sunday in Manhattan. She was 92.

Her daughter Laurie Wenk-Pascal said the death, at NewYork-Presbyterian Hospital, was caused by lymphoma.

With covers instantly recognizable by their varsity-style lettering and soft-focus illustrations, “Sweet Valley High” books enraptured a generation of teenage readers with the lives of Elizabeth and Jessica Wakefield, identical twins attending high school in the fictional Los Angeles suburb of Sweet Valley.

The twins are “the most adorable, dazzling 16-year-old girls imaginable,” Ms. Pascal told People magazine in 1988. They, and the books, are also strikingly innocent: Even as the thoughtful Elizabeth and the scheming Jessica clash over boys, friends and spots on the cheerleading team, drugs, alcohol and sex barely permeate the 181 titles in “Sweet Valley High,” or the scores of others in the spinoffs — and the spinoffs of spinoffs — from the series.

Within a few years of its debut in 1983, “Sweet Valley High” had taken over the young-adult book market. In January 1986, 18 out of the top 20 books in B. Dalton’s young adult best-seller list were “Sweet Valley High” titles. Taken together, the Sweet Valley universe has sold well over 200 million copies.

That juggernaut revolutionized young-adult publishing. Though there had been no shortage of books for teenage readers — and teenage girls in particular — Ms. Pascal recognized their limitless voracity for a compelling narrative and developed a way to feed it.