Patrick Carman's previous books in the Land of Elyon series (The Dark Hills Divide, Beyond the Valley of Thorns, and The Tenth City) have all been New York Times bestsellers. He is also the Creative Director of pcstudio, a packager and pioneer of the multimedia vBook (video+book), a format launched in 2009 with Skeleton Creek. He recently authored the fifth title in Rick Riordan's 39 Clues series, The Black Circle.