This 1993 book examines case studies of North American Quaternary mammalian evolution within the larger domain of evolutionary theory. It presents studies of a variety of taxa (xenarthrans, rodents, carnivores, ungulates) examined over several temporal scales, from a few thousand years during the Holocene to millions of years of late Pliocene and Pleistocene time. Different organisational levels are represented, from mosaic population variation, to a sypsis of Quaternary evolution of an entire order (Rodentia). The book also includes purely theoretical and methodological contributions, for example, on the statistical recognition of stasis in the fossil record, ways to calculate evolutionary rates, and the use of digital image analysis in the study of dental ontogeny. Perhaps the most important aspect of the studies reported in this book is that they span the time between the 'ecological moment' and 'deep time'. The book will interest vertebrate palaeontologists, ecologists concerned with the origin of biological diversity and also evolutionists interested in the competing evolutionary models.