This volume brings together the work of zoologists and palaeontologists from Europe and America who are actively involved in the higher-order systematics of tetrapods (land vertebrates). The relationships and patterns of evolution of the tetrapods are currently much debated, and some key areas of concern are highlighted here. Together with the second volume, this work also presents the latest and most comprehensive overview of the new surveys of large groups within Tetrapoda recently carried out by biologists and palaeontologists. Contributors apply modern cladistic analytical techniques to morphological and molecular data in order to resolve the phylogenetic patterns in much more detail than previously possible. Key questions covered include determining the closest relatives of tetrapods among fish; the relationships of modern amphibians, lizards, snakes, crocodiles, and birds; and the origin and diversification of mammal groups. This is truly a state-of-the-art record of ongoing research, including previously unpublished material by international experts.