The Gulf Coast oil spill's Dr. Doom

As an oil and gas industry insider, Matt Simmons speaks with a bold voice and makes even bolder predictions. His 2005 book, Twilight in the Desert: The Coming Saudi Oil Shock and the World Economy, which argued that Saudi Arabia's oil supplies are way more limited than most people think, raised his profile as an authority on the industry.

For more than 35 years, Simmons has run a Texas-based boutique investment bank, Simmons & Co., which specializes in the energy industry. At times, with his somewhat doom-and -loom-like take on things, there's a hint of conspiracy theorist in his tone. But it's hard to ignore that Simmons is deeply connected and has been pretty much right on in the past: When oil was $58 a barrel the year Twilight was released, Simmons predicted prices would be at or above $100 within a few years. By 2008, when Fortune profiled Simmons, the price of crude had hit $147 a barrel. (more)