The thyroid is an endocrine gland, located at the neck. It secretes three hormones-thyroxine, triiodothyronine and calcitonin. The thyroid hormones influence the metabolic rate of the body and control protein synthesis. Any dysfunction in the production of these hormones or abnormality in the thyroid gland can lead to several diseases. Excessive or insufficient production of the thyroid hormone leads to hyperthyroidism and hypothyroidism respectively. The thyroid gland can also develop nodules which can be malignant or non-malignant. Malignant nodules may include medullary, follicular and papillary carcinomas. Thyroid research encapsulates a wide range of topics relative to the diagnosis, pharmacological and treatment methods, genetics of thyroid disorders and complications, etc. The physiological mechanisms of the action and regulation of the thyroid hormone are studied and understood owing to such research. This book is a compilation of chapters that discuss the most vital findings and emerging trends in thyroid research. The various studies that are constantly contributing towards advancing the understanding of the thyroid gland are examined in detail.