Here's the description:
When seventh grader Georges (the s is silent) moves into a Brooklyn apartment building, he meets Safer, a twelve-year-old coffee-drinking loner and self-appointed spy.
Georges becomes Safer's first spy recruit. His assignment? Tracking the mysterious Mr. X, who lives in the apartment upstairs. But as Safer becomes more demanding, Georges starts to wonder: how far is too far to go for your only friend?
Liar & Spy is an inspired, often-funny story about destiny, goofy brilliance, and courage. Like Stead's Newbery Medal-winning When You Reach Me, it will keep readers guessing until the end.