The Great Learning, The Doctrine of the Mean, The Analects of Confucius and Mencius are all called the four books, which are the basic teaching materials of Confucianism. For hundreds of years, the "Four Books" have been widely circulated in China, and many of them have become popular aphorisms. Among them, The Analects of Confucius and Mencius are collections of speeches by Confucius, Mencius and their students respectively, while Daxue and The Doctrine of the Mean are two books in The Book of Rites. Zhu, a famous scholar in the Southern Song Dynasty, first linked the two. However, before Zhu, Cheng Hao and Cheng Yi had strongly advocated these books. They believe that "University" is an important work taught by Confucius, which was compiled by Ceng Zi. The Doctrine of the Mean is a book "Confucius teaches the mind", and it is a pen, which is written by Confucius' grandson Zisi. Together with The Analects of Confucius and Mencius, these two books express the basic ideology of Confucianism and are the most important documents for studying and treating Confucianism. It is from this perspective that Zhu compiled four books: The Analects of Confucius, Mencius, University and The Doctrine of the Mean. Because of the four representatives of early Confucianism, Confucius, Mencius, Zeng Shen and Zi Si, they are called "Four Books" for short. Zhu annotated these four books respectively, among which the annotations of Daxue and The Doctrine of the Mean were called "chapters and sentences", while the annotations of The Analects and Mencius were called "concentrated notes" because they quoted many other people's sayings. It is worth noting that the order of the four books compiled by Zhu was originally The University, The Analects of Confucius, Mencius and The Doctrine of the Mean, which was arranged in the order of learning from the shallow to the deep. Later generations put The Doctrine of the Mean in front of The Analects because of its short space. For the convenience of engraving and publishing, it became the popular order of The Doctrine of the Mean, The Analects of Confucius and Mencius the year before last. Because Zhu Zhu's "Four Books" not only combines the theories of predecessors, but also has its own unique views, which are applicable to the world; Due to the rising status of "Neo-Confucianism" represented by Cheng Hao, Cheng Yi brothers and Zhu, after Zhu's death, the court approved his four books as official books, which became popular from then on. During the Yanyou period of the Yuan Dynasty (13 14- 1320), the imperial examination was resumed and the book was officially published. Following the yuan system, the Ming and Qing Dynasties developed the "eight-part essay" examination system, and the topic also came from Zhu Zhusi Shu. The four books are not only Confucian classics, but also must-read for every reader. In modern times, the "Four Books" have also been incorporated into primary school textbooks.