"The Clique Series" is a popular book series written by Lisi Harrison. It follows the lives of a group of wealthy middle school girls living in Westchester County, New York. The main character, Massie Block, is the leader of the clique, and the series explores themes of friendship, rivalry, and social status among preteens. The series consists of several novels, starting with "The Clique," published in 2004. Each book delves into the girls' experiences with fashion, boys, and the challenges of growing up, making it relatable to young readers. The series has also inspired a television movie adaptation.