The history books we see now are all written by future generations with reference to different materials. It is not as good as historical records, and the materials cited are different. However, due to the influence of the author's time, position and environment, it will inevitably be mixed with personal feelings, and it will be different from the facts because of the different materials.
For example, the Guangwu Chen Sheng Uprising described in Historical Records was because the Qin law stipulated that anyone who was late to pay was beheaded. But judging from the Qin bamboo slips unearthed in recent years, it is not as serious as beheading. Because the unearthed Qin bamboo slips directly record the decrees of the Qin Dynasty, compared with historical records, the unearthed Qin bamboo slips are first-hand historical materials.
In addition, the notes, works and records made by the parties to major events in history are also first-hand historical materials. First-hand historical materials are highly reliable, but scattered and hard to find, and the description of the event is also vague, which needs us to identify and sort out.