Advice Needed!

I ordered four poker books last week and they arrived today. I have no idea which one I should start reading first. Here is what I ordered:

1. The Tao of Poker
2. Zen and the Art of Poker
3. Tournament Poker and the Art of War
4. Harrington on Hold'em

My goals are to improve my overall play but to concentrate on no limit tournaments, both SNG and MTT. I am finding that I enjoy tournament play much more than ring game play so I want to focus a little more on that. Focus is the other thing I need to work on. I have cut out most of the distractions while playing but my mind still gets scattered about half-way through.

So, which one should I read first?