Powerful product, country, and functional silos are jeopardizing companies' marketing efforts. Because of silos, firms misallocate resources, send inconsistent messages to the marketplace, and fail to leverage scale economies and successes--all of which can threaten a company's survival. As David Aaker shows in Spanning Silos, the unfettered decentralization that produces silos is no longer feasible in today's marketplace. It's up to chief marketing officers to break down silo walls to foster cooperation and synergy. This isn't easy: silo teams guard their autonomy vigorously. As proof of their power, consider the fact that the average CMO tenure is just twenty-three months. How to proceed? Drawing on interviews with CMOs, Aaker explains how to: Strength your credibility with silo teams and your CEO Use cross-functional teams and other strategic linking devices Foster communication across silos Select the right CMO role-- from facilitator to strategic captain Develop common planning