Xerox CEO Ursula Burns made history in 2009. Succeeding Anne Mulcahy, Burns was the first African-American female CEO -- and the first recipient of a woman-to-woman handoff -- in the Fortune 500. She stays grounded by staying true to herself. "When it became clear that I would become the CEO of Xerox, Anne Mulcahy said to me, 'It's going to be hard for you anyway, but don't try and be me. You can't try to be me,'" Burns told Fortune editor-at-large Pattie Sellers last May. "And that's one of the things I learned. You can probably be somebody else and follow all your life, but you cannot be somebody else and lead."