5 Facts About Apple's Tim Cook

He's done it before, now he's doing it again. Tim Cook, Apple's chief operating officer, is taking over day-to-day operations from Steve Jobs while the Apple CEO takes another medical leave.

Five facts about Cook:

1. Waiting in the wings?
Cook filled in for Jobs for two months in 2004 when Jobs was treated for cancer. He was promoted to COO the following year. He filled in again, in 2009, when Jobs took a six-month leave for a liver transplant. Cook won praise for making the company's operations move on time and established himself as the "CEO-in-waiting," according to The Wall Street Journal.

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Apple COO Tim Cook is taking over day-to-day operations from Steve Jobs while he's on medical leave.

2. Lucrative work
Last year, Cook earned $800,000 in salary and took home a $5 million one-time bonus and $52.3 million in stock awards, the Journal reports. The pay package for Cook's time at the helm came at Jobs' request, Reuters reported.

3. A good man is hard to keep
Investors have raised concerns that competitors might lure Cook away. The Journal reports that Motorola and Dell have both made overtures to him.

4. Polar opposites
While Jobs has a larger than life personality, Wired notes, Cook is quite the opposite. He's quiet, soft-spoken and low-key, but also highly organized and energetic, often holding meetings into the night. But like his boss, he's also a health aficionado, munching on energy bars and lifting weights, Wired says.

5. Down Home Alabama
Cook, an Alabama native, graduated from Auburn University, where he majored in industrial engineering. He was described in a CNN Money story as having several interests outside Apple, such as cycling, the outdoors and Auburn football.