Dunkin' Donuts: Bob Rosenberg

In 1963, Bob Rosenberg became CEO of his father's company, Dunkin' Donuts, at age 25. About a decade later, after an overly-ambitious expansion put the company in jeopardy, the board almost threw him out. But Bob matured into his leadership role, developed Dunkin' Donuts into an international success, and accumulated experience from a career spanning 35 years.