Xenotransplantation (xenos- from the Greek meaning "foreign" or strange), or heterologous transplant, is the transplantation of living cells, tissues or organs from one species to another. Such cells, tissues or organs are called xenografts or xenotransplants. It is contrasted with allotransplantation (from other individual of same species), syngeneic transplantation or isotransplantation (grafts transplanted between two genetically identical individuals of the same species), and autotransplantation (from one part of the body to another in the same person). Xenotransplantation is an artificial method of creating an animal-human chimera, that is, a human with a subset of animal cells. In contrast, an individual where each cell contains genetic material from a human and an animal is called a human–animal hybrid. 

In the present book, ten typical literatures about xenotransplantation published on international authoritative journals were selected to introduce the worldwide newest progress, which contains reviews or original researches on xenotransplantation. We hope this book can demonstrate advances in xenotransplantation as well as give references to the researchers, students and other related people.