Memo to T. Boone Pickens: before you write another book about the art of the comeback, make sure your comeback is complete and that your career is on stable ground.

On September 2, Pickens' book The First Billion Is the Hardest: Reflections on a Life of Comebacks and America's Energy Future hit the stores. Now he's in need of another comeback as a huge pullback in energy prices and investor withdrawals have sent the value of Pickens' hedge fund assets down to less than $500 million. When his fund peaked in June, he was managing $2 billion.

With the market in the toilet and investors fleeing for the exits, Pickens has reportedly moved the fund almost entirely into cash -- perhaps a sign that he has abandoned his long-term bullish outlook on oil prices.

However, Pickens' contributions to America now go beyond wealth-building. While he initially made his name as a Carl Icahn-style corporate raider back in the 1980s, he's moved on to finding solutions to our dependence on foreign oil. The Pickens Plan has garnered the support of the Sierra Club, former Clinton Chief of Staff John Podesta, and even Senator Barack Obama -- an impressive feat given that Pickens is an ardent Republican.

And he's not out money yet. Apparently he just gave $63 million to Oklahoma State to pay for a football stadium.