The "Little green book" is a good and valuable read indeed. But that one will not give you a complete overlook and IMO this is not a beginners "Show me the ABC rules of poker"-book. For the beginner it might sometimes be a bit difficult to understand when he is explicitly talking about tournament strategies so some thngs might be misleading if you think "Cash game" while reading. One review put it this way: "Phil breaks down the game into enlightening instructional tidbits and illustrative anecdotes that inspire the kind of persistence and motivation necessary to improve your game."
The tidbit thing makes it a perfect restroom lecture ;-))
Harrington introduced me to poker and I still value that book very much although it may be outdated in several spots by now. The general concepts are explained nicely and I read several parts of it over and over and always find something new.
Regarding Tournament Books: The Poker Tournament Formula by Arnold Snyder was another eye opener for me. Written 7 years ago it might not be the most up to date book but the general approach is interesting and I found lots of cool ideas/concepts and things to think about.
As my questions and problems got more specific I started focussing on forums several months ago. And I must say: This forum here is always a GREAT read with wonderful folks to share with and learn from
Next two books on my list: Crushing the Microstakes by blackrain and I have to continue John A.'s "Polished Poker". Good info for FREE!
And yes... Mindset of Poker or The Poker Mindset. Not about strategy but the psychological aspects which are so extremely important to master.