Thyroid carcinoma is the most common endocrine malignancy. The etiology of thyroid cancer is not yet fully known, although several issues are thought to predispose people, including radiation, nutrition, sex hormones, environment and genetics. This book presents research in the diagnosis, treatment and prognosis of thyroid cancer. Topics include the new paradigm in the cytologic and histologic diagnosis of thyroid cancer; arsenic trioxide in the treatment of iodine non-avid thyroid cancer; thyroidectomy for papillary thyroid microcarcinoma (PTMC); thyroid stimulating hormone and cancer; and the inference and analysis of apoptotic pathways in papillary thyroid cancer.