The Book of Changes refers to three books of changes: Lianshan, Guizang and Zhouyi. Among them, Lianshan and Guizang have been lost, and only Zhouyi has been handed down from generation to generation. Now the Book of Changes is generally called the Book of Changes. The Book of Changes is essentially a book about changes, which has long been used as "divination". Later generations know more about his philosophy, thus becoming a profound dialectical philosophical work.