Eric Topol, director, Scripps Translational Science Institute

In 2006, David Pogue wrote in The New York Times, “Everyone’s always asking me when Apple will come out with a cell phone. My answer is, ‘Probably never.’ ” Not long thereafter, Apple introduced the iPhone. Smartphones are set to become the fastest-adopted technology in history—by 2020, 80 percent of the world’s adults are projected to have one in their pocket.