Ciaffone's Improve your Poker

"The Search Feature is your friend." Yeah, well I've tried it and I must stink at using it because I get a ton of hits for the word "poker" and "improve" but not much on this book. Who has it? How do you guys like it? How much would it help me advance my NL Hold'em game? Thanks for any responses. I've checked it out on his website, the table of contents that is, and it looks okay, but I still cannot grasp if it's based around limit or NL, probably a bit of both.