The Peter Principle holds that we rise to our level of incompetence. In other words, at some point in our career, we all end up in over our heads.
Tom Foster's Management Skills blog has a post on how to find a life preserver when you've reached your own personal Peter Principle moment.
Here's a look on other ways to foil the Peter Principle on How Stuff Works.
Yet more tips on how to avoid your own incompetence.
The Peter Principle revisited offers a refresher on the topic.
The Walrus and the Carpenter blog takes on the idea of the Peter Principle and innovation, which is to say that when a company has a cash cow, it ceases to truly innovate.