The book Pretty Little Liars By: Sara Shepard is about four girls named Aria, Spencer, Emily and Hanna. These four girls were best friends until the summer between seventh and eighth grade when their best friend Allison disappeared. Now the four girls are juniors in high school and they are getting mysterious notes from someone named “A”. These notes are reveling secrets about them that t they thought no one knew. Now these four pretty little liars need to find out whom “A” is and if “A” killed Allison. And put an end to all of this for Alli.