So it was time for him to resign.
He wrestled with the decision for weeks, discussing it with his wife, Bill Campbell, Jony Ive, and George Riley.
"One of the things I wanted to do for Apple was to set an example of how you do a transfer of power right," he told me.
He joked about all the rough transitions that had occurred at the company over the past thirty-five years.
"It's always been a drama, like a third-world country.
Part of my goal has been to make Apple the world's best company, and having an orderly transition is key to that."
The best time and place to make the transition, he decided, was at the company's regularly scheduled August 24 board meeting.
He was eager to do it in person, rather than merely send in a letter or attend by phone, so he had been pushing himself to eat and regain strength.
The day before the meeting, he decided he could make it, but he needed the help of a wheelchair.
Arrangements were made to have him driven to headquarters and wheeled to the boardroom as secretly as possible.
He arrived just before 11 a.m., when the board members were finishing committee reports and other routine business.
Most knew what was about to happen.
But instead of going right to the topic on everyone's mind,
Tim Cook and Peter Oppenheimer, the chief financial officer, went through the results for the quarter and the projections for the year ahead.
Then Jobs said quietly that he had something personal to say.
Cook asked if he and the other top managers should leave, and Jobs paused for more than thirty seconds before he decided they should.
Once the room was cleared of all but the six outside directors, he began to read aloud from a letter he had dictated and revised over the previous weeks.
"I have always said if there ever came a day when I could no longer meet my duties and expectations as Apple's CEO, I would be the first to let you know," it began. "Unfortunately, that day has come."
The letter was simple, direct, and only eight sentences long.
In it he suggested that Cook replace him, and he offered to serve as chairman of the board.
"I believe Apple's brightest and most innovative days are ahead of it. And I look forward to watching and contributing to its success in a new role."
There was a long silence. Al Gore was the first to speak, and he listed Jobs's accomplishments during his tenure.
Mickey Drexler added that watching Jobs transform Apple was "the most incredible thing I've ever seen in business,"
and Art Levinson praised Jobs's diligence in ensuring that there was a smooth transition.
Campbell said nothing, but there were tears in his eyes as the formal resolutions transferring power were passed.