Immunohematology and blood banking is a discipline that bridges science and compassion by providing lifesaving blood and blood products. This concise textbook aims to be a trusted companion for students and practitioners by comprehensively covering the essential principles and practices of these fields. It begins by exploring their historical development before delving into antigen-antibody reactions like precipitation ELISA and radioimmunoassay.A cornerstone is explained - the ABO blood group system including its discovery inheritance genetics and the role of the H substance. Naturally occurring antibodies of this system and practical aspects of blood grouping are uncovered. Other important blood group systems like Rh and clinically less significant ones are also explored.The book navigates various types of whole blood transfusions the vital role of blood donors and phlebotomists and blood collection techniques. Compatibility testing methods like direct and indirect cross-matching are discussed. Transfusion reactions both immune-mediated and non-immune are addressed along with preventive measures.Quality management principles of standards traceability risk management and competency are delved into to ensure blood products meet the highest safety and efficacy standards. An index and appendix aid quick information access. The goal is to impart knowledge and a sense of responsibility to ensure patient safety and well-being through judicious blood and component use.