Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 91-94).This thesis studies the role of the financial system in the amplification and propagation of business cycles. Chapter 1 studies the origin and propagation of balance sheet recessions. I first show that in standard models driven by TFP shocks, the balance sheet channel disappears when agents are allowed to write contracts on the aggregate state of the economy. In contrast, I show how uncertainty shocks can drive balance sheet recessions with depressed asset prices and growth, and trigger a "flight to quality" event with low interest rates and high risk-premia. Uncertainty shocks ...