One day back then, he convened a meeting with his team, and the discussion turned to a particular problem in Asia.

"This is really bad," Cook told the group. "Someone should be in China driving this." Thirty minutes into that meeting Cook looked at Sabih Khan, a key operations executive, and abruptly asked, without a trace of emotion, "Why are you still here?"

Khan, who remains one of Cook's top lieutenants to this day, immediately stood up, drove to San Francisco International Airport, and, without a change of clothes, booked a flight to China with no return date, according to people familiar with the episode. The story is vintage Cook: demanding and unemotional.