This document provides an introduction and overview of hyperthyroidism and hypothyroidism. It begins with an acknowledgment and thanks to God for allowing the completion of the paper. The document then outlines the table of contents and chapters to follow, including introductions, discussions of definitions, etiologies, pathophysiologies, clinical manifestations, and conclusions. The author expresses gratitude for any feedback to improve the document and help nursing students understand these endocrine diseases and appropriate nursing care.