If you dream people reading books, and you are aware of the content of text, it means the message has been built into your dream. The objective is to inform you of the message, via the dream imagery of people reading books. You should pay attention to the message in the content of the book in your dream.
In actual dream, it is very rare for the dreamer who is sleeping, to be able to read a book. The reading is likely to be a message that the brain wishes to impart to the dreamer. Reading is a complicated process that involves the eyes, optic nerves, and brain. Reading can not happen when asleep. If you close your eyes, you can’t read any text or understand what’s in the text. You can know about the message if you have a preconceived idea of what it is going to be about.