<P> Pretty Little Liars is a series of young adult novels by Sara Shepard . Beginning with 2006's initial novel of the same name, the series follows the lives of four girls--Spencer Hastings, Hanna Marin, Aria Montgomery and Emily Fields . </P> <P> The novels have appeared on The New York Times Best Seller list . A television series adaptation loosely based on the novels debuted on June 8, 2010, on ABC Family . The franchise has been licensed by Amazon.com's Kindle Worlds range of non-canon ebooks . </P> <P> The series is loosely divided into four arcs, chronicling the introduction and reveal of each "A". Set in the suburbs of Philadelphia The series follows the lives of four teenage girls nicknamed the Pretty little Liars or simply the Liars, whose clique falls apart after the disappearance of their Queen bee leader, "Alison DiLaurentis". Three years after her disappearance, the girls begin receiving threatening messages from an anonymous character named "A," who threatens to expose their secrets, including long - hidden ones they thought only Alison knew . Shortly after the messages begin, Alison's body is discovered buried in her yard . The books progress with the four girls trying to figure out the identity of "A" and facing many dangerous obstacles and twists as they do so . </P> <P> The series has many characters, most of them recurring . The main characters are: </P>

Pretty little liars in the books who is a