Although blood transfusion saves lives and reduces the rate of morbidity in many clinical diseases and conditions, it is associated with certain risks. A transfusion-related adverse event, also called transfusion reaction, is any unfavourable event occurring in a patient during or after blood transfusion. About 0.5% to 3% of all transfusions result in some adverse events, but the majority of them are minor reactions with no significant consequences. In general, transfusion-related adverse events are categorized as infectious and noninfectious. However, there are other classifications in the literature based on time of occurrence (i.e. acute versus delayed) or physiological mechanism (i.e. immune mediated versus non-immune mediated). A significant proportion of adverse events may occur as a result of errors in preparation, ordering or administration of blood and blood products. This new book contains the latest research in this essential field, which has been revolutionized in recent decades.