First, from the beginning to "all depends on observation", the correct purpose of reading is expounded. First, on the positive side, reading has three different purposes: pleasure, rich color and long talent. Then, the benefits of reading are emphasized. Then, on the negative side, the three biases in reading are pointed out, and the relationship between reading and experience is discussed: they complement each other. Finally, it is pointed out that only people who are sensible can read and use books, and the wisdom of using books is in observing life. From "Don't deliberately question the author when reading" to "Only when you are ignorant can you clearly know", this paper expounds the methods of reading, points out that reading should be carefully thought out, and opposes deliberately picking holes, superstitious books and being limited to literal reasoning. It advocates adopting different reading methods for different books, or choosing to read, browsing, reading through or intensive reading, and some books can only read abstracts. In analyzing the different functions of reading, discussion and composition, From "reading history makes people wise" to the end, it is expounded that reading can shape people's character and make up for various spiritual defects. It also shows that people's mental defects can be made up by reading, just as all diseases in the body can be driven away by exercise.