PrefaceAcknowledgments1. IntroductionThe Early Cenozoic Mammalian RadiationTiming of the Crown-Therian RadiationMammalian Phylogeny, Interrelationships, and ClassificationGeochronology and Biochronology of the Early CenozoicPaleogeographic Setting during the Beginning of the Age of MammalsPaleocene-eocene Climate and FloraOrganization of the Volume2. Mammalian Skeletal Structure and AdaptationsSkullDentitionPostcranial SkeletonSkeletal Adaptations3. The Origin of MammalsWhat is a Mammal?The Evolutionary Transition to Mammals4. Synopsis of Mesozoic Mammal EvolutionHistorical BackgroundThe Oldest MammalsDocodontaMultituberculataEutriconodontaSymmetrodontsEupantotheresTribosphenic MammalsMesozoic Mammals of Uncertain Affinity5. Metatheria: Marsupials and Their RelativesBasal MetatheriansPrimitive Marsupials6. Earliest Eutherian Mammals7. CimolestaDidelphodonta and Other Primitive CimolestaDidymoconidaePantolestaApatotheriaTaeniodontaTillodontiaPantodonta8. Creodonta and CarnivoraCreodontaCarnivora9. InsectivoraLeptictidaLipotyphla10. Archonta: Bats, Dermopterans, Primates, and Tree ShrewsChiropteraDermopteraPrimates and PlesiadapiformesScandentia11. ""Edentates"": Xenarthra and PholidotaXenarthraPholidota12. Archaic UngulatesOldest Ungulate RelativesCondylarthra: Archaic UngulatesArctostylopidaMeridiungulata: Endemic South American UngulatesDinocerata13. Altungulata: Perissodactyls, Hyraxes, and TethytheresPerissodactylaPaenungulata14. Cete and ArtiodactylaCete and CetaceaArtiodactyla15. Anagalida: Rodents, Lagomorphs, and Their RelativesPrimitive Asian Anagalidans and Possible AnagalidansMacroscelideaGlires16. Reflections and Speculations on the Beginning of the Age of MammalsEarly Cenozoic Mammal RecordSynopsis of Paleocene and Eocene MammalsA Final NoteLiterature CitedIndex