Sweet Valley High author Francine Pascal has died at the age of 92.
She died of lymphoma in hospital in New York on Sunday, her daughter Laurie Wenk-Pascal told the New York Times.
Her popular book series about identical US twins Elizabeth and Jessica Wakefield was a hit around the world with its tales of teen romance, friendship and sibling rivalry.
Set in the fictional Los Angeles suburb of Sweet Valley, the first book from the series was published in 1983, with 180 more produced over the following 20 years.
There were also several spin-offs, including Sweet Valley Twins and Sweet Valley University.
The books were translated into 27 languages, selling hundreds of millions of copies worldwide.
There was also an accompanying TV series, starring real-life twins Cynthia and Brittany Daniel, which ran for four seasons from 1994 to 1997.
In fact, Sweet Valley had gone full circle as Pascal had originally planned to sell the idea for a daytime drama featuring teenage characters “until a friend suggested that a book series, rather than a television series, might be the best way to fully develop the fictitious southern California town of Sweet Valley.”
She said some of her ideas came from her three daughters but also from her own experiences of growing up.
Pascal came up with the idea of Jessica and Elizabeth because she “always had a fascination with twins. The trick is to think of Elizabeth and Jessica as the good and bad sides of one person”.
A graphic novel called Sweet Valley Twins was published in 2022.
Pascal’s writing career began in the 1960s, co-writing for the soap opera The Young Marrieds alongside husband John Pascal.
She wrote several other young adult novels before creating Sweet Valley, including Hangin’ Out with Cici, My First Love and Other Disasters and The Hand-Me-Down-Kid.
She also penned adult novels Save Johanna! in 1981 and If Wishes Were Horses in 1994.
