In "The Ascent of Money," Niall Ferguson discusses the role of bills of exchange in finance, highlighting their function as an essential tool for creditors. When a creditor issued a bill on a debtor, it provided a flexible means of transacting that could either serve directly as payment or be converted into cash through a banking intermediary.

This system allowed creditors to manage their financial dealings more efficiently, as they could easily transfer bills to obtain immediate cash, albeit at a discounted rate. The process illustrates the evolution of financial instruments and the importance of trust and credit in economic interactions throughout history.