We survey the major theoretical and empirical findings of the research on the firm's choice between public and private debt, and on the subsequent decision between bank and non-bank private debt. First, we review information-based theories, where banks are information producers, keep the firm's private information confidential, or monitor the firm's actions after the loan. We then review models where banks' advantage over public lenders is in their superior ability to liquidate the firm or renegotiate loan contract terms in the event of financial distress. Finally, we review the evidence on firms' use of different types of private debt. ª 2010 Indian Institute of Management Bangalore. All rights reserved.In the frictionless financial markets conjectured by Modigliani and Miller (1958), capital structure is irrelevant and all of a firm's positive net present value projects are financed. The insight that market frictions make capital structure decisions relevant has spawned a large body of theoretical and empirical research, most of which focuses on the choice between equity and debt financing. Within the class of debt securities, however, firms typically make another choice, namely public versus private debt.Furthermore, a firm that chooses private debt has the choice to borrow from a bank or a non-bank intermediary such as an insurance company. The focus of this paper is on the firm's choice between public and private debt and on the subsequent choice between bank and non-bank private debt. 2 While there are a number of papers that address various aspects of the public versus private debt decisions, to the best of our knowledge there is no paper that synthesises the predictions and findings of the research in this area. Our objective is to present the major theoretical and empirical findings of the research on a firm's decision to choose between public and private debt, as well as among the types of private debt.