In the past thirty years, energy markets have changed from quiet, often heavily regulated areas of the business landscape to some of the most dynamic markets in the world economy. Regulation of oil, natural gas, and electricity markets has been reduced dramatically in the United States and in many other countries. Oil prices have reached record levels with great uncertainty about where they are headed. Drawing on the tools of economics, we study the business and public policy issues that these changes have raised. Topics include the competition in wholesale electricity markets, market power and antitrust, the economics of exhaustible resources, demand efficiency and the transportation of energy commodities. We examine the economic determinants of industry structure and evolution of competition among firms in these industries, investigate successful and unsuccessful strategies for entering new markets and competing in existing markets and analyze the rationale for and effects of public policies in energy markets.