Pretty Little Liars by Sara Shepard

Seventh graders Alison, Aria, Hanna, Spencer and Emily are all best friends in the upper class suburb of Rosewood, Pennsylvania. They trade designer clothes and dish delicious secrets until the night Alison mysteriously disappears at a slumber party. Eventually, Alison is presumed dead, and though the girls are shaken, they each learn to move on with their lives. Though Alison was the unofficial leader of their group, she could be manipulative and mean, and she wasn’t above using the secrets she discovered about each of them against them. Now, three years later, the girls are shocked when each of them begins receiving menacing email and text messages from someone simply signed “A.” This person seems to know everything about them, including the dirty little secrets each girl believed that Alison took to the grave. Who is “A”? Has Alison really come back from the dead? And if so, is she going to use what she knows to ruin their lives? This completely addictive series sucked me in faster than an episode of Desperate Housewives. Don’t start this one unless you have the sequel, Flawless, on hand, or else the suspense just might kill you!