For almost thirty years, Brookings Papers on Economic Activity (BPEA) has provided academic and business economists, government officials, and members of the financial and business communities with timely research of current economic issues. Contents include: Articles "Technical Progress and Co-invention in Computing and in the Uses of Computers"" by Timothy Bresnahan and Shane Greenstein "Causes and Consequences of Airline Fare Wars" by Steven Morrison and Clifford Winston "Pharmaceutical Innovations and Market Dynamics: Tracking Effects on Price Indexes for Antidepressant Drugs" by Ernst R. Berndt, Iain M. Cockburn, and Zvi Grilches "Power Struggles: Explaining Deregulatory Reforms in Electricity Markets" by Matthew W. White "The Welfare Impacts of Competitive Telecommunications Supply: A Household-Level Analysis" by Frank A. Wolak