Book excerpt: One of the most respected marketing gurus in the world shows why some of today's biggest brands are having trouble and how to avoid repeating their mistakes. It wasn't long ago that Levi-Strauss, Xerox, Crest, AT&T, Firestone, and Digital Equipment dominated their respective markets. What happened to undermine their standings and of those of other superbrands? Are their declines simply the inevitable consequence of change and the birth of new competition? In this important predecessor to the classic Differentiate or Die, "the king of positioning," Jack Trout answers that question with a resounding "No!" Writing in his signature, straight-from-the-hip style he reveals the disastrous marketing and strategy blunders that led to the dissolution of the most recognized superbrands. He clearly shows how those mistakes could have been avoided. With the help of in-depth case studies chronicling the events leading up to the falls from grace of Sears, Miller Brewing, Xerox, Crest, Burger King, and other past market leaders, he identifies the ten most common mistakes that big brands make, and he develops a set of expert guidelines for marketing managers and executives on how to build, protect, manage, and expand their companies' brands and avoid brand-killing blunders.