Guoxue is variously translated as Traditional Chinese Thoughts, Culture, and Learning (abbreviated as Chinese Learning), Traditional Chinese Classics, National Learning, Ancient Chinese Classics, Traditional Chinese Culture, among others. It encompasses a wide range of key concepts that are central to understanding Chinese culture, philosophy, history, religion, literature, and society. These concepts represent a foundational understanding of Guoxue, providing insights into the values, beliefs, theories, and traditions that have shaped Chinese civilization for over five millennia. In this book, we introduced the terminology for Guoxue from 12 aspects: Confucianism, Classic Studies, Daoism, Buddhism, Ethics, Etiquette and Customs Studies, Politics, Economics, Literature, Linguistics, Historiography, and Philosophy.