The halogen book is an important part of the imperial system in China feudal society. Generally interpreted as "guard of honor", in fact, the content covered by halogen books is much richer than ritual. "Bitterness Book" devoted itself to and directly served the major activities of the emperor. The purpose of the trip is different, and the ceremony is different. Since the Han Dynasty, it has also been used for queens, princes and princes. More than four items made in the Tang Dynasty were given halogen books.

The halogen book appeared in the Han Dynasty. There is a saying in Cai Yong's "Arbitrary": "The son of heaven comes out, followed by the driver, which is called a halogen book." "The History of Guan Bai in the Later Han Dynasty" said: "Every time the Emperor went out, he played music on the halogen book and controlled it with his master." Han Yingshao's "Han Guan Yi" explained: "When the emperor was driving, he was named Lu, and both soldiers and guards were called books, so he was called Lu Shu." The word "Lu" in the ancient "Lu Shu" is the general name of "Ling", which means "big shield". . Jia Yi wrote in "On Qin" that "the corpses on the ground are everywhere, and rivers of blood flow", which means that the battlefield is fierce, and countless people who died in battle have rivers of blood, which can float a big shield. From the protective significance of the shield to the protective measures for the emperor, including weapons and equipment and organized actions of guards.

The "book" of the halogen book is the meaning of the book, that is, the "number of drivers" and the scale, quantity and grade of security personnel, that is, the equipment, are all written in classics. After more than 2,000 years' development, the system of halogen books in China feudal society has become more and more complete. On the basis of driving and protecting, sacrificial ceremonies (holding golden melons, Baoding and flags) and music and dance (music performances and dance performances) were also added.