SAN FRANCISCO?Apple co-founder and chief executive Steve Jobs announced he was taking a medical leave of absence on Monday, 18 months after returning to the company following a liver transplant.
"At my request, the board of directors has granted me a medical leave of absence so I can focus on my health," Jobs said in a three-paragraph email to Apple employees which did not specify his latest health issues.
Jobs, 55, the Silicon Valley legend behind the Macintosh computer, the iPod, iPhone and iPad, said he would continue as chief executive "and be involved in major strategic decisions for the company."
He said chief operating officer Tim Cook, who took over when Jobs went on nearly six months of medical leave in January 2009, would be "responsible for all of Apple's day to day operations" during his absence.
"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," he said.
"I love Apple so much and hope to be back as soon as I can," Jobs said. "In the meantime, my family and I would deeply appreciate respect for our privacy."
Jobs underwent an operation for pancreatic cancer in 2004 and received a liver transplant in Tennessee while on medical leave in 2009. He returned to public view in September 2009 looking gaunt but healthy.
The announcement of his latest health issues came with US markets closed for the Martin Luther King Jr. holiday and could be a shock to the high-flying tech giant.
Apple shares had tumbled in late 2008 when rumors swirled about his health after he failed to show up at the Macworld Expo.
Apple's share price has surged since his return, however, and in May, Apple surpassed Microsoft as the largest US technology company in terms of market value. The only companies with larger market capitalization than Apple's are ExxonMobil and Petrochina.
Apple shares closed at a record high of $348.48 on Wall Street on Friday.
Apple is scheduled to release its fiscal 2011 first quarter results after the markets close on Tuesday.
The company's fortunes have been uniquely linked to Jobs, who returned to the flagging company in 1997 after a 12-year absence and introduced innovative and wildly successful products like the iPod and iPhone.
Questions about Jobs' health have resurfaced periodically since the cancer diagnosis, and have been the subject of much debate among corporate governance experts over the obligations the company has to its shareholders.
Britain's Financial Times last month named Jobs its "Person of the Year" and even US President Barack Obama joined in the plaudits to the chief executive of the Cupertino, California-based gadget-maker.
"We celebrate somebody like a Steve Jobs, who has created two or three different revolutionary products," Obama told reporters at a White House news conference.
Jobs and Steve Wozniak founded Apple in 1976 and introduced the first Macintosh computer in 1984 along with innovations such as the computer mouse.
Jobs left Apple in 1985 after an internal power struggle and started NeXT Computer and Academy-Award-winning Pixar, maker of hit animated films such as "Toy Story."
Apple, meanwhile, stagnated until Jobs returned to the company in 1997.
Since then, Apple has gone from strength to strength, starting with the iMac in 1998, the iPod in 2001, iTunes in 2003, the iPhone in 2007, the App Store in 2008 and the iPad last year.