This issue of Brookings Paper on Economic Activity contains articles and reports presented at the thirty-first conference of the Brookings Panel on Economic Activity, which was held in Washington, D.C., on April 9 and 10, 1981. Four articles address economic issues of current importance: the causes of the slowdown in productivity growth, the impacts of financial innovations and their implications for monetary policy, and the importance of oil prices and other economic developments on currents account balances and exchange rates. Two shorter reports examine the problems with traditional mortgages and retirement annuities in a period of inflation, and the characteristics of price expectations by business during the 1970s.