The rise of Apple CEO Tim Cook, the most powerful business leader in the world

On August 24th, 2011, Tim Cook took the job as CEO of Apple, leaving many wondering if he could fill the massive void left by his friend and mentor, Steve Jobs.

Today, five years later to the day, Apple is the most valuable company in the world, and products like the iPhone continue to rule the market, leaving Cook looking pretty good.

But when he was first announced for the role, he was a big question mark. He's a quiet guy who had long stayed in the background at Apple, while Jobs did the big product releases and the press tours.

What a lot of people don't know is that Apple would never have gotten where it is without Cook's help early on in Jobs' reign - if not for Cook's expertise and willingness to do what needed to be done, Apple would have been sunk.

Here's how Tim Cook rose through the ranks, became a major leader in the reinvention of Apple, and ended up at the helm of the most-watched company in the world.