This monograph on the biology of animal building embraces all groups, from simple invertebrates to primate toolmakers. It looks at the behavioral and anatomical equipment animals have in order to build, as well as the materials available to them. It examines how architects are able, singly or collectively, to produce complex structures often much larger than themselves. It also looks at the costs of building, the properties of completed structures, the ecological impact of them ,and their effects on the evolution of animal builders.