Pretty Little Liars is an American teen drama, mystery–thriller television series loosely based on the popular book series of the same title, written by Sara Shepard. The show premiered on June 8, 2010 on ABC Family. After an initial order of 10 episodes, ABC Family ordered an additional 12 episodes for season one on June 28, 2010. These episodes began airing on January 3, 2011 and ended on March 21, 2011. The ratings success of the first 10 episodes prompted the book series to be extended beyond the initial eight novels.