Primarily intended as a textbook for the undergraduate and postgraduate students of Biosciences, Biotechnology and Biochemistry, this compact and well-organized text now in its Second Edition introduces a chapter on Immunity to Infectious Agents. The book gives complete coverage of all the key topics in modern immunology without excessive detail or theoretical discussion. Each chapter is enriched with numerous well-labelled illustrations. Beginning with an introduction to the immune system including different types of immunity, immunogens and immunoglobulins, this text covers the basic concepts of antigen antibody interaction and various methods of deter-mining them. It also includes topics on lymphocytes, Major Histocompatibility Complex (MHC) and its classes, graft rejection, and complement pathways. The book concludes with a description on different types of vaccines, and cytokines which are a group of regulatory proteins.