Steve Jobs (search), the charismatic chief executive of Apple Computer Inc. (AAPL) and Pixar Animation Studios (PIXR), said Sunday he had surgery to remove a cancerous tumor from his pancreas but added he expects a full recovery.

In an e-mail message to employees released by Apple, he said he will be off to recuperate during August and expects to return to work in September. The message did not specify where Jobs underwent the surgery.

He identified his cancer as an islet cell neuroendocrine tumor (search), which he described as rare and said could be cured by surgical removal if diagnosed early. He said his was caught early and would require no chemotherapy or radiation treatment.

A far more deadly — and common form — of pancreatic cancer is adenocarcinoma, he said.

"I mention this because when one hears 'pancreatic cancer' (or Googles it), one immediately encounters this far more common and deadly form, which, thank God, is not what I had," he said in the message.

During Jobs' absence, Apple will be run by Timothy Cook, the company's executive vice president of worldwide sales and operations. Cook said the current management team has worked with Jobs for many years, and that experience will guide them through the next month.

"Steve is an extremely hands-on CEO," said Cook. "We have some very clear priorities for the company for months to come."

Bill Campbell, an Apple director, said the board is confident Cook can manage the company in Jobs' absence. He also expressed relief that Jobs' surgery went well.

"The surgery was hugely successful, and the prognosis is excellent," Campbell said. "We feel very relieved and optimistic about the future."

Jobs, 49, and friend Steve Wozniak founded Apple Computer in 1976, five years before IBM Corp. jumped into the personal computer market.

In 1984, the company released the Macintosh, which was the first commercially successful computer to have a graphical user interface that mimicked a physical desktop. It was eventually copied by IBM-clone computers, which became far more dominant.

A year later, Jobs left Apple following a struggle with the company's board. He cashed in some Apple stock and formed another computer company, NeXT (search).

But NeXT took too long to release its "mainframe on a desk," and once it was available in 1989, it was criticized for its $4,000 price. Within four years, NeXT abandoned the hardware market and announced it was focusing on operating system software.

By then, Apple was struggling and efforts to upgrade its operating system were going nowhere. In 1996, Apple bought NeXT. In 1997, Jobs was brought back as an interim chief executive. In 2000, "interim" was dropped from the title.

He made a splash in 1998 with the release of a revamped and stylish iMac, which was followed by new lines of laptops as well as professional-grade computers and servers. In 2001, Apple jumped into the digital music player business with its iPod, which is now the most popular.

And last year, Apple launched the iTunes Music Store (search), which allowed legal music downloads after Jobs persuaded music companies that his technology was secure.

It also helped that Jobs also owned an entertainment company.

Before his return, he also had paid $10 million to buy a special effects computer business from filmmaker George Lucas. The company eventually became Pixar and released such classics as "Toy Story," "Finding Nemo" and "Monsters, Inc."