"The Old Book of Tang" is a historical work by the Chinese historian Liu Shu, which was written in the 8th century. This book describes in detail the history of the Tang Dynasty, which ruled China from the 7th to the 10th centuries. The author tells in detail about the reign of Chinese emperors, events, political and social changes of that period. The book is considered one of the key sources for the study of Chinese history and Chinese culture in the Middle Ages. Thanks to the "Old Book of Tang", the reader can better understand the complex processes that took place during this period of Chinese history.