This sourcebook provides information about immune system function and related disorders. Readers will learn about primary and secondary immunodeficiency diseases, hypersensitivity, cancer immunotherapy, and autoimmune diseases, including celiac disease, Behcet disease, systemic lupus erythematosus, VEXAS syndrome, and myasthenia gravis. Moreover, readers will get to know about symptoms, diagnostic tests, and drugs and therapies, along with tips for coping with autoimmune and immune disorders, suggestions for glossaries of terms related to immunology and a directory of additional resources.