The four books, collectively known as Daxue, The Doctrine of the Mean, The Analects of Confucius and Mencius, are the most famous Confucian classics and must-read books for ancient scholars in China, with great influence. Zhu, a famous Neo-Confucianism scholar in the Southern Song Dynasty, used the research results of the former sages for reference and put forward his own unique views to express the essence of Neo-Confucianism, thus forming Four Books Notes (also known as Four Books Notes).

Zhu Xi spent his whole life writing Notes to Four Books, which became his most famous work and the most important research document of Neo-Confucianism in Song and Ming Dynasties. So there are many versions, which are widely circulated. Among them, the version of Wu Ying and Wu Zhizhong's father and son in Jiaqing period of Qing Dynasty is better in the current version. This time, I will take this as the basis, participate in other popular books, and follow the good ones. In order to facilitate modern readers' reading reference, in addition to using horizontal simplified Chinese characters, the characters in the semi-original text are specially moved to the back of the paragraph for centralized comments, indicating that the note numbers are consistent with the original text.