YA novelist Sara Shepard (pictured, via) will add another four books to her Pretty Little Liars series. The first book will be called Twisted, and is scheduled for a July 2011 release.
The series was originally supposed to conclude with the eighth book. According to Shelf-Life, the decision to continue the series came because the ABC Family adaptation “has been a ratings success and renewed interest in the books.”
The series’ first season returns to television in January 2011. Shepard debuted as an author with the Pretty Little Liars series. Since then, she has released an adult novel, The Visibles, and started a second YA series, The Lying Game.