The majority of patients with both hypothyroidism (under-active thyroid) and hyperthyroidism (overactive thyroid) are experiencing autoimmune diseases that cause these conditions. When autoimmune thyroid disease results in hypothyroidism, the term for the disease is "Hashimoto's thyroiditis". When the autoimmune disease of the thyroid causes hyperthyroidism, it is called "Grave's Disease". Thyroid antibodies attack key proteins in the thyroid gland and in some cases, stimulate production of excessive amounts of hormone. These killer cells that are manufactured by the immune system become confused for reasons yet to be fully understood by medical science and they begin to identify thyroid cells as threats in the body. As they attack these cells, the thyroid gland becomes damaged, resulting in inflammation, enlargement of the gland (goiter) and thyroid hormone imbalances. This audiobook is not intended to be an extensive manual but is intended to contain information most often sought by laypersons on the subject.