1. An overview -- 2. The innate immune system -- 3. B cells and antibodies -- 4. The magic of antigen presentation -- 5. T cell activation -- 6. T cells at work -- 7. Secondary lymphoid organs and lymphocyte trafficking -- 8. Restraining the immune system -- 9. Self tolerance and MHC restriction -- 10. Immunological memory -- 11. The intestinal immune system -- 12. Vaccines -- 13. The immune system gone wrong -- 14. Immunodeficiency -- 15. Cancer and the immune system