I have the same book and, as you found out, it's a book about Limit Hold'em, which I usually play. That being said, it is still a good book in terms of hand selection, pot odds
, and implied odds, and the thinking process involved in putting players on hands. But, if all you play is No Limit cash games, you MUST read Harrington's two volumes on Cash Games. For tournaments, Harrington's 3 volumes on NL tournaments are the way to go. With these three sets of books, you've got all 3 variations of Hold'em covered.