+1 for the Pokerstars online school. Free, it covers Multi table tournaments, Cash games, Sit n go's and single table tournaments, as well as bankroll management, teaches you about position etc etc.
I've done the online school, and it got me to a decent point where I actualyl played smarter and started making money. However now I feel like I'm ready for the next step in poker, and am looking into advanced reading.
Short version: Pokerstars online school as a bare minimum, then once you're comfortable with that, get a book thats more advanced / focused on 1 single game type (Tournament play, cash game etc)