A 40-year path of friendly arguments and groundbreaking studies of how governments weigh policies to deal with economic troubles has led a pair of prominent economists to share the 2011 Nobel Prize in their field. Princeton University professor Christopher Sims was honored along with Thomas Sargent, a New York University economist and visiting professor this semester at Princeton, for developing tools to analyze the economic causes and effects of monetary policy. Their work has revolutionized the field of macroeconomics and how it is applied by central banks and governments around the world. Sims, who is Princeton's Harold H. Helm '20 Professor of Economics and Banking, has been a faculty member at Princeton since 1999, and is the third tenured faculty member at Princeton to win the Nobel Prize in economics in the past decade. He and Sargent are longtime colleagues, and are currently teaching partners for a graduate course at Princeton. The day was highlighted by the insistence of both men to proceed with teaching their classes -- while also accepting the worldwide interest in their research -- and lighthearted banter over their career-long history of disagreements within the field. Both Sims and Sargent remarked on the prize with humility.