Zhang Ji is a famous thinker in history. He is the founder of the Confucian school and is known as one of the "four public figures in pre-Qin". His academic achievements are outstanding. His main works are The Analects of Confucius, The University and The Doctrine of the Mean, among which The Analects is his most important work and is known as the "Confucian classic".

Zhang Ji also published the famous Book of Rites, which recorded the essence of China's ancient etiquette culture. Zhang Ji's thought has far-reaching influence and is considered as the basis of China's ancient philosophy.

Zhang Zeyu is Zhang Ji's grandson. He is a famous thinker and one of the representatives of Confucianism. His most famous work is Zhang's Poems, which contains many classical poems and has an important influence on China's ancient literature. Zhang Zeyu once wrote The Doctrine of the Mean, which profoundly explained and expanded Zhang Ji's The Doctrine of the Mean, and had a great influence at that time.