Some people say that Raiders Up and Down is the most mysterious book known after contact with the supernatural. They are two books that were widely circulated in folklore before 1980s, but gradually disappeared in recent years.
There is no way to find the source. There are two books. It is said that one can only learn one of them, otherwise the whole family will die suddenly. I don't know if it's true or not. The best policy is to protect wealth, scholars have no heirs, and the worst policy is to honor future generations. Scholars have been miserable all their lives. Learners look at life and know life and death.