The oldest and most complete book in the world is the Book of Changes, which has been preserved for more than 4000 years. The Book of Changes was an ancient divination book that contained many aspects of politics, philosophy, morality, culture, and so on. It was preserved in the Museum of Chinese History and was one of the oldest and most complete ancient books in the world. Due to its excellent preservation conditions, it still retained many of its original unique contents and styles, which became an important part of Chinese culture.