Gr 3–5—Each volume presents clues related to 12 "mysteries," with solutions and explanations on the following page. Aside from the simple word problems in Math Mysteries, however, prior knowledge will get readers farther than reasoning or observation skills since they are asked to solve mysteries based on a few vague clues. For example, they must deduced that a certain animal is an opossum based on the facts that it's fuzzy and gray, related to a kangaroo, and plays dead. Moreover, despite the series title, only the history mysteries are related to actual cases or incidents. Capped by perfunctory final riddles with the answers given in plain sight just below, these volumes may draw budding naturalists, historians, or math geeks, but they won't give them much practice in gathering evidence or drawing conclusions.