Rumors about Steve Jobs’s health surfaced again after he didn’t show up at the Apple iPhone launch on Verizon Wireless in New York last week, as was expected. This morning Apple released the following email to all Apple employees:

Team,

At my request, the board of directors has granted me a medical leave of absence so I can focus on my health. I will continue as CEO and be involved in major strategic decisions for the company.

I have asked Tim Cook to be responsible for all of Apple’s day to day operations. I have great confidence that Tim and the rest of the executive management team will do a terrific job executing the exciting plans we have in place for 2011.

I love Apple so much and hope to be back as soon as I can. In the meantime, my family and I would deeply appreciate respect for our privacy.

Steve

A few things are certain. Apple’s stock fell 6.2 percent in Frankfurt, Germany, for European trading. That’s up from a nearly 10 percent dip earlier in the day. Some are suggesting it could take as much as a 15% hit tomorrow when the U.S. exchanges reopen.

The timing of the announcement is worthy of note. Today is a holiday; tomorrow Apple will announce their earnings for Q1 2011 (scheduled for 2:00pm Pacific Time, it will be liveblogged here). Because it includes the holiday quarter, earnings could be the best quarter ever.

Apple is in excellent shape, with strong seasoned leadership:

“It is natural that investors will expect the worse,” said Charles Wolf, an analyst with Needham & Company, noting that Apple has a history of “minimal disclosure” and “obfuscating” details about Mr. Jobs’s health.

Mr. Wolf said that regardless of whether Mr. Jobs returns to Apple, the company would probably continue doing well for the foreseeable future, though its long-term prospects are more uncertain.

“Right now Apple has a management team that is one of the greatest in American business,” Mr. Wolf said. “Whatever trajectory the company is on will continue for two to five years, regardless of whether Steve comes back.”

In January 2009 Jobs took a leave of absence and secretly flew to Tennessee for a liver transplant. After an initial stock hit, Apple recovered to near record-highs by the time Jobs returned.

MG Siegler, the guy at TechCrunch known for writing about Apple, expects Apple to do even better this time. Apple has a well established rhythm for its products — iPhone in June, iPod in September, expect the new iPad in April — they’re queued up in the pipeline and expected to arrive as planned. Says Siegler:

The wildcard is new products. While we’re in a bit of a lull of rumors following the iPad unveiling last year, you can be sure that Apple has other things they’ve been dreaming up in the meantime. One I wouldn’t bet against for a few years out, for example, is an actual television. For these types of things, Apple needs Jobs — until they can prove otherwise.

There has been a lot of talk about Apple’s head of design, Jonathan Ive, taking over the “visionary” role from Jobs (he’s also been mentioned as a possible CEO successor in the past). There’s no question that with hit after hit after hit, Ive has the design skills necessary to make the best products in the world. But what about software? One key to Apple is the tight relationship between the hardware and the software. Ive is the industrial design guy — hardware. Would he need a software counterpart? Would that be the head of iOS software, Scott Forstall?

Or would Ive be able to work alongside Cook to form a fully functional Apple without Jobs around? Is Jobs the glue that holds the entire operation together? Only those high up inside Apple will know that for now.

Anything else is guesswork. As to Jobs health, Kara Swisher sums it up this way:

Jobs has had a persistent and very serious illness he has been fighting successfully for many years now.

But his outlook, from the moment he found out about his particular form of pancreatic cancer, has never been really good.

More to the point, his ability to bounce back several times has been both heartening and more than a little miraculous.

But, remember this: Both times he has taken time off for health reasons, Jobs has come back with fierce and game-changing innovation.

The iPhone came out after his first big bout with his illness, the iPad after the second.

Today, it’s happened a third time and I suspect much of what will be written about his diagnosis will be sheer speculation and only a little bit will be accurate reporting.

I am guessing this time too that Jobs will be as tight-lipped as ever about what he’s going through, which could be a wide range of medical issues, some more serious than others.

And that, I think, should be what everyone should let him do, because the public Steve Jobs has given his large audience more than enough since he got back after the last time he was sick.

I never got to see a Jobs product introduction in person. The man is a stupendous performer who has achieved some remarkable highs. I hope one day he’s able to do another. Until he does, he deserves the privacy he’s asked for.