This PDP summarizes the papers presented at the 2005 Summer Workshop on Money, Banking, and Payments at the Cleveland Fed. Papers covered a wide variety of topics in monetary theory and policy, banking, and payments systems research. Topics ranged from optimal monetary policy, optimal bank contracts, the private supply of money, the coexistence of credit, money, and capital, the design of payment systems, and international currencies. Effort was made to calibrate models and bring them closer to the data. These contributions illustrate the progress made in the field of monetary theory.