During Jobs's six-month leave in 2009, Apple's stock under Cook's leadership rose 67 percent, . In fact, Apple's board of directors--in a move nominated by Steve Jobs himself-- with a $22 million bonus for his work in Jobs's absence; that works out to about $3.6 million each month he filled in for his boss. (With those bonuses, Cook's total compensation neared $60 million for 2010.)

While Cook's work ethic and detail-oriented mind are frequently lauded, some analysts have questioned whether--despite his undergraduate design degree and years at Apple--he has the design chops that Jobs brings to the table. "Tim Cook's the guy who makes the trains run on time," said Roger Key of Endpoint Technology Associates in a . "He's not the creative genius... Even though in some sense he is an excellent manager and is the backstop for Steve ... that's not going to do anything except make the trains run on time. That's not going to decide what the train should look like in five years."

CNN, however, quotes Gartner analyst Carolina Milanesi as saying, "There is a lot of respect for Tim Cook internally at Apple and externally, and he has proved to be able to drive the company well."

Of course, as has explained in the past, . While Jobs's contributions are obviously many, Cook provided some insight into the company's operations when asked about Jobs's health on :

There is an extraordinary breadth and depth and tenure among the Apple executive team. And these executives lead over 35,000 employees that I would call all "wicked smart." And that's in all areas of the company, from engineering, to marketing, to operations, sales, and all the rest.