NL hold em

[JackSevenSuited]

I have been playing poker for about a year now, online for about 8 months and believe i am beginning to understand the game, however i know there is always room to improve. I have read Phil Gordons books and felt they gave me a good introduction to the base concepts of the game however they are rather light. I am looking for about 2 books i can purchase for each type of play: cash game and tournaments. Since there is so many poker books out there im just looking for any recommendations. Thanks.

PS. I'm only interested in No limit hold em.