Brookings Papers on Economic Activity (BPEA) provides academic and business economists, government officials, and members of the financial and business communities with timely research on current economic issues. Contents: Editors' Summary Heeding Daedalus: Optimal Inflation and the Zero Lower Bound By John C. Williams The Age of Reason: Financial Decisions over the Life Cycle and Implications for Regulation By Sumit Agarwal, John C. Driscoll, and Xavier Gabaix Interpreting the Unconventional U.S. Monetary Policy of 2007-09 By Ricardo Reis By How Much Does GDP Rise If the Government Buys More Output? By Robert E. Hall When the North Last Headed South: Revisiting the 2930s By Carmen M. Reinhart and Vincent R. Reinhart