Apple's Chief Operating Officer Tim Cook is back again at the helm, after CEO Steve Jobs announced that he is going on a medical leave.

However, questions galore as to whether the man who smoothened out Apple's supply chain can replace visionary CEO Steve Jobs. CNN had reported in 2008 that when posed with a similar question, Cook had replied Come on, replace Steve? No. He's irreplaceable, that's something people have to get over. I see Steve there with gray hair in his 70s, long after I'm retired.

ABC reported that Piper Jaffray Co. analyst Gene Munster, talking about Cook, said he is as much an operational genius as Steve Jobs is a product genius. Cook's operational skills are underscored by the fact that he currently handles Apple's worldwide sales, operations, supply chain, service and support.

Cook's relation with supply chain is best described by an anecdote reported by CNN, related to the period when Cook joined Apple in 1998 to straighten the operational morass that Apple was in. In a meeting convened to tackle a problem in China, he had said: This is really bad someone should be in China driving this. Thirty-minutes in the meeting he chided Sabih Khan, the then operations executive, saying Why are you still here?. Khan responded by immediately booking a ticket to China, sans a change of clothes.

Before joining Apple, Cook was vice president of Corporate Materials for Compaq, handling the product inventory. He had also been with IBM for 12 years as director of North American Fulfillment overseeing manufacturing and distribution functions. He also worked with Intelligent Electronics as COO of the Reseller Division.

Cook, 50, holds a Bachelor of Science degree in Industrial Engineering from Auburn University and an MBA from Duke University where he was a Fuqua Scholar.

He is also on the list of board of directors for Nike and National Football Association which explains his obsession with fitness, primarily cycling and football. Cook is known to idolize Lance Armstrong. He also dresses casually like Steve Jobs with a minor departure in sneaker brand, wearing a Nike while Jobs is a New Balance man.

Cook is one of the pillars behind Apple's two pronged strategy which involves developing stellar products through its thorough marketing and design efforts which allows it to charge a premium while striving to bring down the cost of product simultaneously, thus reaping the difference in profits.

Cook is pretty close to the two business icons, Steve Jobs and Nike's Phil Knight. Both the companies have a shared strategy in which they outsource production to low-cost areas while they maintain control over their core competency, which is design and marketing.

In his last stint during Job's absence, the company's value skyrocketed 67 percent during his tenure of six months, says a CNN report. Apple has apparently rewarded Cook handsomely for his efforts as Forbes revealed that Cook received $59 million in total compensation in the year 2010, which included salary of $800,000 and $5 million in cash bonus.

A lifelong bachelor, who still lives in rented house, Cook also had his tryst with a killer disease when he was misdiagnosed with multiple sclerosis in 1996.

However, whether the relentless Cook who begins work at 4:30 am is the apt replacement for Jobs is still disputed on the ground that he is not a product visionary. His success as a CEO depends on his capability to surround himself with people who can offset his weakness, like the way Jobs has Cook to iron out operational nitty-gritties.

While the upcoming shareholders' meet will decide whether a CEO succession plan will be implemented, Jobs can until then feel secure that the company would be in good hands.