This book focuses on four energy commodities -- crude oil, unleaded gasoline, natural gas, and heating oil -- and Commodity Futures Trading Commission's oversight of these commodities. Specifically, this report examines (1) trends and patterns of trading activity in the physical and energy derivatives markets and the effects of those trends on prices; (2) the scope of CFTC's authority for protecting market users from fraudulent, manipulative, and abusive practices in the trading of energy futures contracts; and (3) the effectiveness of CFTC's monitoring and detection of market abuses in energy futures markets and in connection with energy-related enforcement actions. This is an excerpted, edited and indexed version of a GAO report.