This is an introduction to the concepts taught by Michael Porter, and succeeds in that mission perfectly. Written with simple elegance, it conveys important concepts very clearly and thoroughly.
The author provides a lot of meat in a slender volume, using Porter's teachings to lay out exactly what a strategy should be and must do for a company. What is a strategy, what real competitive advantage means, and how a strategy must be flexible while staying consistent with the best of the firm's existing (and unique) ways of doing things.
Sometimes when I read a book I'll dog-ear a page or two that I find important. In this case there was simply way too much content that I'd have to return to again: I wound up reading the thing with a highlighter in hand.
I've now lent it to a colleague at the office, and am using the concepts in this book as a guide in studying the "five forces" surrounding the startup I'm working for, and hopefully deriving a strategy that meets the objectives laid out by Porter.