Is there anything about music in The Book of Rites? Which ones? Are there any classic books about music theory?

"All sounds are born by people's hearts, moved by people's hearts, made of things, and moved by things, so the sound shape corresponds to the sound, so it changes."

(The Book of Rites and Music). Reference Interpretation: Music is produced by people's hearts. The reason why people have this "touched" psychological and emotional state is because things and things in the world have touched him. So he uses sound to express the image of something, and uses sound to correspond to all kinds of things, so music is extremely rich and varied. )

"Happiness is happiness, and human feelings are inevitable, so people don't like coke."

(Xunzi's Theory of Music. Reference Interpretation: "Happiness" comes from "music". People's emotions are innate, so people can't live without music. )

"Stand in ceremony, succeed in pleasure" (Confucius, The Analects of Confucius. Reference interpretation: man's social attribute is because he can understand the basic composition of society; And if a person doesn't know music, he can't be considered a perfect person. )

Other works include Zhu Zaiyu's Complete Music and Zhu Quan's The Secret Spectrum of Magic in Ming Dynasty.