The Greek economy experienced a boom until 2007, followed by a prolonged depression resulting in a 25 percent shortfall of GDP by 2016. Informed by a detailed analysis of macroeconomic patterns in Greece, we develop and estimate a rich dynamic general equilibrium model to assess quantitatively the sources of the boom and bust. Lower external demand for traded goods and contractionary fiscal policies account for the largest fraction of the Greek depression. A decline in total factor productivity, due primarily to lower factor utilization, substantially amplifies the depression. Given the significant adjustment of prices and wages observed throughout the cycle, a nominal devaluation would only have short-lived stabilizing effects. By contrast, shifting the burden of adjustment from taxes toward spending or from capital taxes toward other taxes would generate significant longer-term production and consumption gains.