The good acceptance of this textbook is an indication that it has served its purpose. The present edition has been prepared in order to cover the main progress achieved in the five years that have elapsed since the first edition. The structure of the book remains essentially the same but a con siderable amount of new material has been introduced, particularly in certain areas such as the genetics of immunoglobulins and T cell receptor, the regulation of the immune response, hypersensitivity reactions, and cellular immunology. Today, immunology is essential for biologists in general and in...