Transplantation is the process of replacing cells, tissues, or organs from one site to another for repairing damaged or diseased organs or tissues. The study of the response of the immune system when an organ or tissue is grafted from one person to another is termed as transplantation immunology. The immune system is a significant barrier to successful organ transplantation when done between individuals. It identifies the transplant as foreign object in certain instances, which triggers responses in the body to reject it, and ultimately destroy the transplant. The immune system needs to be manipulated to ensure the long term survival of the transplant. This book traces the progress of this field and highlights some of its key concepts and applications. It unfolds the innovative aspects of transplantation immunology which will be crucial for the progress of this field in the future. This book can prove to be an essential guide for all those who are interested in this field.