If you're scanning this article, you have probably played a house game or two, maybe some online Texas Hold Em. You are also researching to improve at poker. Texas Hold Em is an easy game to understand, but very complex, which you may uncover the more you play.
All books will likely be linked at the end of the article
If playing in money games, you ought to get Phil Gordon's Little Green Book and focus it. After you finish, Harrington on Cash Games 1 and a couple of. While you are reading, it's also wise to be playing online, preferable somewhere cheap. Once you have gotten the hang of those two books, read Ryan Fee's guide on 6max. This book is very useful, but uses a lot of short hand you will get from the first three books. While you happen to be reading and playing, enroll in the forums on Two Plus Two. Post some hand histories and get some feedback in your game. You can also watch some video tutorials, some is found at Deuces Cracked.
If you happen to be playing in tournaments, Harrington on Hold'Em 1, 2, and 3 are perfect substitutes for Harrington on Cash Games 1 and 2.
Reading these books and forums, a lot of shorthand is thrown around. It is not scientific, much more of a means for folks to share with you common situations. There will almost never be a 100% correct way to experience a hand, it's more a skill when compared to a science. Similar to chess, people have a variety of playing styles, poker online and no one is correct.
Phil Gordon's Little Green Book: Lessons and Teachings in No Limit Texas Hold'em by Phil Gordon
Harrington on Cash Games, Volume I: How to Play No-Limit Hold 'em Cash Games by Dan Harrington
Harrington on Cash Games, Volume II: How to Play No-Limit Hold 'em Cash Games by Dan Harrington
Harrington on Hold 'em Expert Strategy for No Limit Tournaments, Vol. 1: Strategic Play by Dan Harrington
Harrington on Hold 'em Expert Strategy for No Limit Tournaments, Vol. 2: Endgame by Dan Harrington
Harrington on Hold 'em Expert Strategy for No Limit Tournaments, Vol. 3: The Workbook by Dan Harrington