you can read in dreams but there’s no “continuity” of what you’ve read – within the dreamscape, you think (or you tell yourself) you’re continuing to read a book you’ve read in real life
this lack of “continuity” is one of the main tricks of lucid dreaming – read something twice (ex. time on a digital watch (not an analog watch)) – if the content changes, you’re dreaming – the secret of lucid dreaming is if that change triggers enough frisson for you to “wake up” inside the dream without kicking you out of the dream completely