The immune system has evolved as a protection from pathogenic attack. It is immensely complicated and our appreciation of this complexity increases year on year as new research reveals yet more secrets. Understanding the immune system is crucial for both medical and bioscience students. There are many books out there that offer in-depth introductions to the subject, but none that offers such a personable and practical overview of the nuts and bolts of the immune system as "How the Immune System Works".This third edition of "How the Immune System Works" provides a perfect introduction to the essential principles of the immune system, covered in humorous but highly informative ''lectures''. Perfect for exam preparation or as an enjoyable overview of a difficult subject. New features of this edition include: more material on cancer and the immune system; expanded coverage of immune system regulation with a new chapter ''Turning off the Immune Rsponse''; and a new chapter on immunological memory and vaccines.