Life Without Martha

At the peak of her company's success, Martha Stewart inadvertently summed up both the strength and vulnerability of the media empire she had built. At an advertising-industry conference in Detroit in 2001, the lifestyle guru was fielding questions from a star-struck audience. "Someone asked her, 'You dispense all this advicewho taught you all these things? Who's your mentor?'" recalls Samir Husni, a magazine consultant who also spoke at the conference. "She said, 'Me. Me. I did it all by myself.'"

That relentless self-reliance helped turn Stewart into a wealthy tycoon. But the future of Martha Stewart Living Omnimedia,...