"茶經" by Lu Yu is a monograph written between 760 and 762 CE during China's Tang dynasty. This pioneering work represents the world's first known systematic study of tea and tea culture. Divided into ten chapters, it explores everything from tea's mythological origins and cultivation methods to brewing techniques and regional comparisons. For Lu Yu, tea symbolized the harmony and mysterious unity of the universe, reflecting the religious thought of his age across Buddhist, Taoist, and Confucian traditions.