Sumner Redstone built his Viacom empire via a combination of "vision and paranoia," The Economist says, taking his father's exhibition chain, National Amusements, and future-proofing it against emerging paradigms and technologies, such as pay-TV and VCRs. Now 92 and too frail to attend his conglomerate's increasingly anxious investor meetings, Redstone finds his empire challenged by another wave of innovation that it might not be so prepared to handle this time. That is the upshot of this compelling Economist feature, which can be read here.