Immunology is a fast evolving subject, and attempt has been made in this work to keep it as much up-to-date as possible according to the requirement of the students and researchers in the field. Immunology is the study of how the body defends itself against disease. It helps us understand how the immune system is tricked into attacking its own tissue, leading to diseases like rheumatoid arthritis, diabetes or allergy. Immunodeficiency disorders involve malfunction of the immune system, resulting in infections that develop and recur more frequently, are more severe, and last longer than usual. Biochemistry is the study of how cells work at molecular level. Biochemistry, and the related field of molecular biology, are important in understanding the molecular basis of life and its role in the disease process. Biochemistry is the investigation of the molecular basis of life. Throughout the history of this scientific discipline, biochemists have worked to reveal the fundamental chemical and physical principles that underlie living processes, their success is demonstrated in the enormous impact that the biochemical approach has had on the life sciences. This book reviews the principles of immunology and biochemistry, provides basic concepts of it by extracting the important information on immunology and peasants it in a concise, uncluttered fashion to prepare students for their courses.