Few people have had such strong influence on macroeconomics in general and on the New Keynesian School of macroeconomics as Mark Gertler has. His work with Ben Bernanke and Simon Gilchrist on the role of credit and financial conditions on business cycles, and with Ben Bernanke on whether the central banks should respond to asset price bubbles, are some examples of his influential work. Mark Gertler is the Henry and Lucy Moses Professor of Economics at New York University, and visited the Reserve Bank of New Zealand for the Monetary Policy conference held in Wellington on 17-18 December 2009. The conference was organised jointly by the Reserve Bank of New Zealand and the Center for International Economic Development to mark the 20th anniversary of inflation targeting in New Zealand. Ozer Karagedikli from the Economics Department of the Reserve Bank interviewed him.