Over one million people world-wide have benefited from successful tissue and organ transplants and survival rates have dramatically improved. But transplantation has become a victim of its own success. The demand for human organs can no longer be met and deaths of persons on waiting lists have more than doubled since 1988. A number of alternatives have been proposed to fill the gap between the supply and demand of organs and the past few years have seen the development of various approaches derived from recent advances in biotechnology. Among these technologies is xenotransplantation - the transplantation of viable cells, tissues and organs from one animal species to another. Xenotransplantation of cells and tissues has been approved for clinical trials in a number of OECD countries. However, opinions about the risks from these early procedures and whether to proceed any further vary. At the New York 1998 Workshop on "International issues in transplantation biotechnology including the use of non-human cells, tissues and organs", world leaders in the field reported on the state of the art and unmet needs in transplantation, addressing in particular the potential, the risks, the ethics and socio-economic impacts of xenotransplantation. Based on presentations, transcripts of round-table discussions and comments raised at the workshop, this book provides an overview of the field and of current regulatory frameworks and addresses the most pressing international policy considerations on xenotransplantation.