Just because you have a breakthrough business idea doesn’t mean you’re the right person to communicate it. Which brings us to Michael Porter. His essay “What Is Strategy?” is one of the most-reprinted articles in the history of Harvard Business Review, but I defy you to find anyone, including Porter himself, who can explain that article’s ideas about strategy and competition with the elegance and precision those ideas deserve. You can now, though, thanks to Joan Magretta’s Understanding Michael Porter. Magretta, once a student of Porter’s and subsequently a Bain partner, divides her book into laying out and answering, clearly and conclusively, two of the central questions of business: What is competition? What is strategy? She shows how Porter makes the two questions smash into and bounce off of each other. If you want to understand why competition leads to mistakes in strategy, when strategy is “an antidote to competition,” and how you can use Porter’s often-cited-but-rarely-understood five forces to gain practical insights into how your company and its competitors are performing, you’ve come to the right place. And in a Q&A that Magretta conducts at the end of the book with Porter, the man himself finally makes sense. We read this and, if you want to make better decisions about your business, you should too.