The Darwinian struggle of business keeps getting more brutal as competitive advantage gaps get narrower and narrower. Anything you invent today will soon be copied by someone else--probably better and cheaper. Many companies thrive during the early stages of their life cycle, only to fall slack during periods of inertia and die out while others surge ahead. But as Geoffrey Moore shows, some notable companies have figured out how to deal with Darwin in their mature years--making changes on the fly while fending off challenges from every quarter.