This animal encyclopaedia combines hard facts about a particular animal with interesting details about its lifestyle, behaviour, other members of its family, and habitat and conservation. It contains details of more than 2,000 animals of all types, from armadillos and wallabies to sea cucumbers and fish eagles, arranged thematically from the smallest animal to the biggest. The book is divided into two main parts, invertebrates and vertebrates. The sections are arranged according to animal classes. In invertebrates, the sections are simple animals, cnidarians and comb jellies, flat worms, round worms and ribbon worms, segmented worms, molluscs, arthrods and echinoderms. In vertebrates, the sections are fish, amphibians, reptiles, birds and mammals. There are also special features scattered throughout the book that focus on general animal subjects such as hibernation, aestivation, colour and camouflage.