The instant New York Times bestseller from the author of the Newbery Medal winner When You Reach Me: a story about spies, games, and friendship. The first day Georges (the S is silent) moves into a new Brooklyn apartment, he sees a sign taped to adoor in the basement: SPY CLUB MEETING\u2014TODAY! That\u2019s how he meets his twelve-year-old neigh\u00adbor Safer. He and Georges quickly become allies\u2014and fellow spies. Their assignment? Tracking the mysterious Mr. X, who lives in the apartment upstairs. But as Safer\u2019s requests become more and more demanding, Georges starts to wonder: how far is too far to go for your only friend? \u201cWill touch the hearts of kids and adults alike.\u201d \u2014NPR Winner of the Guardian Prize for Children\u2019s Fiction Named a Best Book of the Year by The New York Times, The Wall Street Journal, and more!