The Alfred Kropp series is a trilogy of young adult fantasy novels written by American author Rick Yancey. The first book, The Extraordinary Adventures of Alfred Kropp, received a starred review from Publishers Weekly,[1] was named a Publishers Weekly Best Children's Book of the Year[2] and was a finalist for the Carnegie Medal.[3] The second book, Alfred Kropp: The Seal of Solomon, received a positive review from Publishers Weekly[4] and was released in May 2007. The third book, Alfred Kropp: The Thirteenth Skull, was already written and on the store shelves for sale, but was announced by Yancey in Publishers Weekly in April 2006