Comparison, first of all, is a concept of time-literature is a record of all kinds of knowledge. Time is like a chain, with "the present" as the clue. The former is called "the past" at this time, and the latter is called "the future": time is history, and files produced in the past time are called historical files; Today's literature is called contemporary literature. And "now", this time chain, is extremely unstable and fleeting. When philologists set out to sort out and study some contemporary documents, it has actually become a historical existence. So this book uses the concept of time in Historical Documents. All subordinate documents are propositions of historical documents, which were put forward as far as possible when collecting documents, from ancient times to 50 years after the founding of the People's Republic of China. Secondly, from the perspective of discipline system, generalized history first includes the changes of nature and the development of human activities. It covers a wide range of historical documents. It includes all the works in the world, and what we usually call historical literature refers to the history of human society, which is the so-called narrow history. Historical records refer to the historical classics in the classified entries of ancient stages, including modern texts. Literary works in the classification of history, philosophy and classics are relative to any catalogue classification. Therefore, most departments except the history department actually belong to historical documents, and ancient and modern studies have long been discussed. Zhang Xuecheng's "Reporting Sun Yuan as a Book" said, "It's nothing more than asking about geography." It can be seen that Ishikawa's textual research on Historical Records is not limited to four historical books; Zhang also put forward the proposition that the Six Classics are all historical materials. As early as more than two thousand years ago, Sima Qian wrote Historical Records based on the Six Classics. He put forward the idea of "giving different versions of the Six Classics and sorting out his own miscellaneous words", which was widely used. However, if the four classics are regarded as historical documents, they are historical documents in a broad sense, which are no different from all documents and are confusing; If you stick to the history department, you will lose to intolerance. C "Mix and match is not clear. Keep it and you will pass "(Zhang Xuecheng: a candle explains the case), that is, the so-called" too much is not enough ",too wide and too narrow are all disadvantages. The historical documents examined in this book are mainly narrow branch classics, but four broad documents are summarized, among which the historical materials are not selected. The priorities are clear. There are three important ways for China to accumulate historical documents. First, the accumulation of official archives; second, the increasing number of historical narratives; third, the development of various narratives other than history books.