The scary thing about Apple is that although it is the most valuable technology company in the world, its success has almost always appeared to hinge on the presence and leadership of co-founder, Steve Jobs. Memories of Apple, sans Jobs, in the 80's and 90's still sends shivers down the spines of both fanboys and stock analysts alike.

So now with Jobs out again on medical leave (this time for an indefinite period, no less) anxiety is running high once more. Who is COO Tim Cook, anyway? We know he kept Apple together during earlier medical leaves for Jobs back in 2004 and, again, in 2009. Can he do it again? Will he be tested for a longer period this time (perhaps even permanently)?

For those that remember the Sculley years, it was the best of times and the worst of times. It's hard to say former Apple CEO John Sculley did a bad job in the ten years from 1983 to 1993. After all, he grew it from an $800 million dollar company to $8 billion.

That being said, it was under Sculley's watch that Apple rolled over to Microsoft licensing part of the Mac's user interface to keep from losing the Mac version of Word. Product lines became too fragmented and confusing for the consumer. Apple internally balkanized into fiefdoms. As for innovation; when people think of John Sculley they think of the Apple Newton. When they think of Steve Jobs, they think of the Mac.. and the Mac... and the Mac.. and then the iPod, the iPhone and now the iPad (and don't forget the Mac).

People, fear not! Tim Cook is no John Sculley. Apple will be okay, with or without Steve Jobs for the forseeable future (and let's hope his recovery is swift for reasons more important than supplying the rest of us with cool tech toys).

Here's why we shouldn't worry:

1. He's done this twice before. As mentioned, Cook filled in for Jobs in 2004 when he had surgery related to pancreatic cancer and again in 2009 when he had the liver transplant. Apple stock took an initial dip in the early days due to jittery traders. That quickly passed and, for example, share prices actually went up 67% during the five months that Cook ran the show in 2009.

2. Apple is more than cool toys. Yes, it's all about the toys. But, those toys wouldn't see the light of day and Apple wouldn't have the profit margins it does without running a tight, efficient ship on the back-end. I'm speaking of supply chains, dealing with manufacturers and wireless carriers, inventory control, pricing and all those other not-so-sexy parts of the business that make or break the business itself. Apple is as innovative when it comes to operations, as it is dreaming up new products we all want to buy. Make no mistake, Tim Cook is the genius behind operations at Apple. He's the guy who manages all those pieces whether Jobs is in the office or not and he's been doing it for years. In fact, Tim Cook has been at Apple since 1998. Think about how Apple has transformed since then.

3. Apple is a well-oiled machine at the height of success right now. For now, the company could almost run itself. There's no mystery about what's on tap for Apple this year. As surely as the sun will rise and set in the morning, you can bet there will be an iPhone 5 in June-ish, an iPad 2 this spring and a new version of the Mac OS later this year. The big visionary decisions are set in stone already (Steve Jobs' forte). That leaves the mechanics of delivery and execution (Tim Cook's forte).

4. Despite making his bones at the likes of IBM and Compaq, Tim Cook is no outsider within Apple fighting the culture. He went native along time ago. Stories abound of his rapid acclimation to Apple upon arrival 13 years ago. Fairly early on, Jobs moved his office close to his own because they were so simpatico.

5. Tim Cook has clearly been blessed and annointed by Jobs, himself. The one thing Cook lacks is that he's not Jobs. Jobs is more than a CEO, even more than a co-founder. He is an icon. For many, he is Apple. That makes him a tough, if not impossible, act to follow. Whether this is temporary or permanent, a vote of confidence from the big guy makes all the difference. I can't help but think of the San Francisco 49ers back in the 80's and 90's when it was a football dynasty under quarterback Joe Montana. When Joe retired, back up quarterback Steve Young took the helm. Who knew at the time he would be as great as Joe in his own way and style. I can't help but see Tim Cook playing Steve Young to Steve Jobs' Joe Montana.

One last footnote about Cook: Speaking of football, he is an Auburn graduate and subsequently a rabid fan by all accounts. Now, it makes sense why he wasn't at the BCS championship game last week.