Typical brand wars of the industrial era include titanic confrontations such as GM v. Ford v. Chrysler or, in consumer goods, Pepsi v. Coke. In the late 1990s, the ‘new economy’ sector of personal computers (PC) produced a comparably aggressive war in which Microsoft, Intel, and Dell poured millions into their advertising budgets in the hope of being recognized as the premier PC brand. A moment’s refl ection reveals something distinctly different about that last grouping. Althought certainly another battle of giants, it was, in one way at least, quite unlike the battle between the ‘big three’ car manufacturers, for Microsoft provides software and Intel provides microprocessors for Dell computers. These three live in the same supply chains; GM, Ford, and Chrysler do not. Microsoft v. Intel v. Dell was, nonetheless, a brand war, this chapter argues, because brands play an important role in the ‘vertical’ competition (Bresnahan and Richards 1999) between complementary fi rms within a supply chain. Within chains, that is, fi rms that must cooperate often engage in a struggle against one another both to control and to resist being controlled. Thus, certain supply chains may be quite as predatory as the food chain, for the spoils from these ‘zero sum’ supply chain struggles are signifi cant. For the victor, they may produce increasing returns; for the loser diminishing returns. This chapter sets out to explain how these struggles develop and what part brands play in them.2