I read them, I wish there was a way to menu the ones already found so I could re-read or save for later. I totally agree with @1mirg that some books are not in a good place to stop.
Yes. All of them, including notes, scrolls and any other scribblings I stumble across. This was one of my most pleasurable pastimes in previous games.
Two of my characters in particular seek them out quite deliberately. But then I can't walk past a bookshop without popping in to browse.
Only one I really read was the Lusty Argonian maid books.
Anything else I quickly spammed cancel to exit out of the book.