Jobs Letter a Temporary Salve for Apple

Beyond Jobs, there isn't a clear successor.

Apple's management bench isn't all that deep with visionaries. The company's No.2 executive is operations chief Tim Cook. According to a recent story in Fortune, Cook comes across as a very effective behind-the-scenes manager, but maybe a bit too wonky for the center stage.

For now, word from Jobs that he's alive and getting better helps. But investors will continue to worry about Jobs' and Apple's health as the company enters more bruising times.