100 Trillion Good Bacteria Living in the Human Body

Gr 3–7—These titles are crammed with photos, diagrams, charts, and graphic designs. Many pages also feature numbers, especially large ones; for instance, Animal Kingdom features a time line of animal life starting 3.5 billion years ago. Incorporating so many topics per volume results in uneven quality. For example, Space has excellent visual representations of Earth's daily rotation and yearly orbit, but the moon landing diagram partially covers explanatory text. The series' UK origin is apparent in the lists of suggested books, which have limited U.S. availability. Some facts are questionable, such as the claim that the Yanomami have lived in the Amazon for 50 million years, and a diagram appears to indicate that a kangaroo can leap 30 feet high. Poisonous Plants devotes only two pages to toxic varieties. Rockett includes in each book a disclaimer that "the numbers will most likely be an estimation" and may change with time.