Well... a lot of people, really. Kate William wrote a great deal of them. There were a lot of people who wrote the books, but the concept was often thought-up by the fountain-head herself Francine Pascal. She came up with the whole design of "Sweet Valley."
She eventually wrote one of the books itself--the ten-year reunion "Sweet Valley Confidential."
The Sweet Valley High series was created by Francine Pascal, and the first book in the series was published in 1983. There were more than 180 Sweet Valley High books in total, with the final one released in 2003.
Although the Sweet Valley High series ended, there were numerous spin-offs, including Sweet Valley Confidential, Sweet Valley University, Sweet Valley Kids and so on.
The first book in the Sweet Valley High series, "Double Love," was published in 1983.
Sweet Valley High - 1994 Single in Sweet Valley 4-14 was released on: USA: 1997
Sweet Valley High - 1994 Sweet Valley Night Fever 3-19 was released on: USA: 1996
Sweet Valley High - 1994 is rated/received certificates of: Australia:G
Research has shown that Sweet Valley High is not a location but is rather a name for a novel series as well as a television program. The novel series is about identical twins that attend Sweet Valley High in Sweet Valley, California. The television series was based on the novels and ran from 1994 to 1996.
Sweet Valley Confidential, March 29, 2011 -- continues the story 10 years laterPascal has released a new branch of the series post-Confidential: "The Sweet Life."
Sweet Valley High - 1994 Model Behavior 2-2 was released on: USA: 18 September 1995
Sweet Valley High - 1994 Summer Lovin' 2-1 was released on: USA: 11 September 1995
Sweet Valley High - 1994 Surfing the Nets 3-7 was released on: USA: 11 April 1996
Sweet Valley High - 1994 Oracle on Air 1-2 was released on: USA: 12 November 1994
Sweet Valley High - 1994 A Fair to Remember 2-7 was released on: USA: 23 October 1995
Sweet Valley High - 1994 Mixed Doubles 2-12 was released on: USA: 27 November 1995
Sweet Valley High - 1994 The Quick and the Blonde 2-11 was released on: USA: 20 November 1995