I don't know what to vote for. I have only read one book "Moorman's Book of Poker" and I still haven't finished it. I bought it years ago.
I believe the best way to learn is to watch a pro like Lex Veldhuis, easywithaces, Spraggy, James Staples and Talonchick on Twitch.
Also good ones like training sites, Raise your edge, Upswing, run it once, Advanced poker training, Tournament poker edge and Red chip poker.
Your poll needed more options to choose from, if you had added Twitch, that would of been my answer.
You will have some free access to Raise your edge on youtube as they have added free videos to help your game. Gripsed is also good on youtube. Tournament poker edge has also got some videos that you can watch on youtube. Red chip poker is also on youtube too, so just look at a poker training site and see if they have uploaded some free videos for you to get stuck into.
Hope that helps