Amanda Valentino changed everything.

Callie Leary has exactly one thing, and one thing only, in common with Nia Rivera and Hal Bennett: They were each chosen by Amanda to be her guide. When Amanda arrived at Endeavor High, she told Callie she moves around a lot and always picks one person to help her navigate the choppy waters of a new school. Why did Amanda lie?

Following a course that they suspect Amanda deliberately plotted, Callie, Nia, and Hal piece together some cryptic clues. But they find more questions than answers and quickly realize that before they can figure out what happened to Amanda--the girl who changed their lives--they'll need to solve the most important mystery of all: Who is Amanda Valentino?

"There are far too many scintillating, hand-clenching facets to this carefully crafted whodunit to count. Doors are purposefully left open and clues expertly planted (in the book's text, artwork — even the endpapers — and on a dedicated Web site readers can explore), all of which will compel readers to pick up the subsequent books in the interactive Amanda Project series. (The books, all appearing under the name Stella Lennon, will be written by various authors, with Melissa Kantor [Girlfriend Material] kicking things off.) In the opener, three unlikely allies — narrator Callie, a member of the exclusive 'I-Girls' clique; Nia, the 'biggest freak in the ninth grade' — cum — hidden beauty; and Hal, an 'uber-cool' artist — are brought together as they attempt to find 15-year-old Amanda, who has disappeared. The story unfolds at just the right pace to build curiosity, but not overwhelm with unanswered questions (Why did Amanda tell Callie, Nia and Hal three separate stories about her past? What's up with the animal totems she gives them?). If there's too much high school social politics at points, the catty backstabbing is unlikely to distract most readers from the mind-bending mystery shrouding Amanda's whereabouts. Ages 12 — up. (Sept.)" Publishers Weekly (Starred Review) (Copyright Reed Business Information, Inc.)

"Pretty Little Liars" meets "The 39 Clues" meets "Cathy's Book" in this exciting new series that's a collaborative, interactive adventure for girls that begins in the books and continues online.