The animal kingdom is staggeringly diverse, but the animals that most easily spring to mind - the tigers, elephants, eagles and crocodiles, or perhaps amphibians, fish, insects and even humans - account for only a tiny proportion of known species. What's more, there are estimated to be many tens of millions still unknown to science. Animal Earth is an unbiased tour of this world, highlighting the bizarre appearances, hidden lives and mostly small scale of the creatures with whom we share our planet. The bewildering number of animal species are all offshoots from a relatively small number of lineages, all sharing a common body plan and evolutionary history. This book provides a broadly equal summary of each of these thirty-five lineages, and is structured according to the latest research on the evolutionary relationships of the animals. Every species is an integral component of the ecosystem we live in, and as intelligent beings it is our duty to protect and understand animal diversity not only for its own sake but also to maintain the natural systems that keep us and everything else alive.