I've been into IT consulting and online marketing for ten years now, and was pretty sure I knew the tricks of the trade - until I read this awesome book. It's one of the best selling marketing manuals ever written, and, whilst being quite funny at times thanks to the military metaphors, provides you with excellent examples of basic and advanced strategies.
Of course, most examples the authors bring are not new to people who are in the business - we all heard about the cola and burger wars, but they are presented in an entertaining yet profound way.
The three things that annoy me about the book are that:
(a) they have copied a little too much from Sun Tzu and samurai literature
(b) they often forget that there are more subtle ways of bringing down an enemy than tanks - to stay in the books military slang, and finally
(c) it often seems (!) they completely ignore that there are ethics even in a corporate world. They do not, but all Patrick Batemans out there will just ignore lines like: "The problem with marketing today is not just the lack of rules. The biggest problem of all is the failure to realize that one ought to have rules in the first place."
All in all, an excellent book for professionals and amateurs alike, which should, however, not be taken too seriously at times.