In 10 pages of text, each with one or two sentences, these slim volumes offer basic introductions. Large, double-spaced type and simple structure will help newer readers, though words like "parasites" and "herbivore," defined only in the glossary, may pose challenges. The sequence of facts jumps from topic to topic sometimes abruptly, but a nice mixture of broad and specific details makes the information easy to digest. The full-page color photos opposite each text page are serviceable, but rarely exciting; most present solo views of predators, for example, with no sign of the animal it hunts. Though the series is not essential, individual titles may fill subject holes.