(FORTUNE Magazine) – The fact that Apple chief Steve Jobs will be sitting out the month of August to recover from surgery to remove a small, cancerous tumor has prompted more than meditations on his mortality. It has also reminded everyone who follows high tech how much Jobs, 49, personifies Apple. Indeed, most people would be hard-pressed to name any other Apple executive. Jobs likes it that way, not because he is an egomaniac but because he has always feared that competitors might poach his team if he publicized their skills. While Jobs is out, here are the four key players who will be in charge (and no, this is not a hiring guide!). Tim Cook, executive VP--a 43-year-old operations whiz and a veteran of Compaq and IBM, he will be Steve's main stand-in; Jon Rubinstein, senior VP, iPod division--the 47-year-old hardware engineering specialist works closely with Jobs and has been the go-to guy for the ways to build Apple's elegant devices; Avie Tevanian, 43, chief technology officer--another longtime Jobs associate, he is the godfather of OS X, the slick new operating system for the Macintosh that many believe is the most advanced in the world; and Phil Schiller, senior VP for marketing--a programmer by training, the 44-year-old dreamed up features in many of Apple's sexiest products. He also works closely with Jobs on Apple's ad campaigns. --Brent Schlender