Oral history cannot last long, so oral credibility is not as good as historical books, such as Historical Records, which have been used by later generations and become official history.
So is the history book completely credible? Not exactly. There is a saying that history is written by winners. So how can we learn more real history? Contrast+corroboration. But this is really difficult, not to say that it is difficult to operate-of course it is, and what is more difficult is that you need to accumulate and precipitate historical knowledge. Your literacy should be able to guide you to pay attention to the relevant direction, and find relevant historical materials in that direction, and find clues that can be used to prove or compare those historical materials that are considered relevant.
But don't worry. Look at historical materials, don't be preconceived, it is important to find out who wrote them. For example, the Ming history is the official history written after the victory of the Qing Dynasty. Then all the words in it were corrected. Emperor Chongzhen was not in a coma, but his personality defect was not enough to govern the country. Although Yuan Chonghuan opposed the Manchu Dynasty, he was killed by his own emperor. Li Zicheng is a bandit (indeed) and so on. The purpose of this description is to tell the Han people that part of the reason for the demise of the Ming Dynasty was that its own emperor was not worthy to be emperor, and another reason was the destruction of bandits and thieves. This will have the purpose of appeasing the Han people. To this end, the real history and events must of course be revised. So what should we do? On the one hand, official history is still serious after all, on the other hand, it can be verified through local chronicles, collections of scholars at that time and mutual books.