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.