"Imagine being Tim Cook in 2011. At age fifty, you're enjoying a superb career. You've been a senior executive at Apple since 1998, its head of global operations since 2007, and its acting CEO during your boss's medical leaves. But you can still enjoy a quiet life, away from the spotlight. No one is tweeting about you or stopping you on the street. Then your boss resigns in late August and dies six weeks later, unleashing a worldwide outpouring of...