It really depends on who wrote the book. I don't really care about whether it's on papers or on a screen. I was once quite confident about my knowledge on PHP

It really depends on who wrote the book. I don't really care about whether it's on papers or on a screen. I was once quite confident about my knowledge on PHP (version 5), thought I learned it all. Then I brought a book from O'Reilly for the newbies in the team, flipped a few pages before handover, learned a few new damn things myself. I would totally recommend to read a book while learning a big topic (such as a language, framework etc). There are so many things that if you know, you'll be a better user. Yes, so many things change, but, so many things don't. Plus, you can buy another book to learn the new knowledge. With that said, I want to go back and remind: know the author and read the review before you buy, don't waste your time on bad books.