The book covers the evolution, biology and natural history of the group of flightless birds that includes ostriches, emus, cassowaries and kiwis - the Ratites and their relatives, the Tinamous. It reviews the scientific studies that have been made of their ecology, behaviour, physiology, husbandary, evolution, mythology and conservation. Each of the 55 species is described in detail, with maps of the present known distribution, accounts their food and nesting habits, calls, field identification, habitat and relationship with humans, including farming. It is the first such comprehensive account of the groups since 1877, and the first to bring together comprehensive information about the tinamous, little known birds of the America. It reviews the long debated subject of the evolution of these groups, highlighting new evidence that has turned many old theories on their head. Both the interested amateur and the professional should find it rewarding to read.