Book excerpt: This book focuses on the evolution, biogeography, systematics, taxonomy, and ecology of New World and Australasian marsupials, greatly expanding the current knowledge base. There are roughly 140 species of New World marsupials, of which the opossum is the best known. Thanks to recent research, there is now an increasing amount of understanding about their evolution, biogeography, systematics, ecology, and conservation in the Americas, especially in South America. There are also some 270 marsupial species in the Australasian region, many of which have been subject to research only in recent years. Based on this information and the authors’ extensive research, this book provides comprehensive insights into the world's marsupials. It will appeal to academics and specialized researchers, students of zoology, paleontology, evolutionary biology, ecology, physiology and conservation as well as interested non-experts.