"The Doctrine of the Mean" is a monograph on moral philosophy in ancient China that discusses the realm of life and cultivation. It originally belonged to the thirty-first chapter of the "Book of Rites" and is one of the Confucian classics. It is said to have been written by Zisi during the Warring States Period. The content affirms that "the mean" is the highest standard of moral behavior, regards "honesty" as the noumenon of the world, believes that "sincere" reaches the highest level of life, and proposes "learned, interrogated, deliberated, discerned , The learning process and method of understanding.
Scholars in the Song Dynasty took "The Doctrine of the Mean" from the "Book of Rites" and collectively referred to it as the "Four Books" with "Daxue", "The Analects" and "Mencius". After the Song and Yuan dynasties, it became a school official-appointed textbook and required reading for the imperial examination, which had a great influence on ancient Chinese education and society.