There’s nothing predictable about this alphabet book other than the order of the letters themselves. B follows A, G follows F, and so on. But X is for armadillo, and the reason why is the only thing that’s readily explained in this book full of riddles about the animal skull pictured for each letter from A to Z. “Every skull tells a story. Be a detective,” invites author Jerry Pallotta. “Why would a cow be on the J page?…H is for . . . . Here is the only creature on the earth that can read this book!” The answers for each letter take a little detective work, too. They can be found in small type on a double-page spread near the book’s end. One other puzzling aspect to the book is the incorporation of U.S. presidential portraits into Ralph Masiello’s illustrations. While a bit of a stretch conceptually (granted, they are heads), they won’t distract from the overall appeal of the volume, and for kids who just can’t get enough of brain-teasers, they may actually add an inviting dimension. (Ages 7-10)