Renowned scholar Arjun Appadurai argues that the economic collapse of 2008, while indeed spurred on by greed, ignorance, weak regulation, and irresponsible risk-taking, was ultimately a failure of language. To prove this point, he takes us into the world of derivative finance, which is now the core of contemporary trading and the primary target of blame for the collapse. Through his incisive analysis, Appadurai draws on thinkers such as J. L. Austin, Marcel Mauss, and Max Weber as theoretical guides to showcase the ways language?and particular failures in it?paved the way for ruin. He also highlights the importance of derivatives in contemporary finance, isolating them as the core technical innovation that markets have produced. shows that derivatives are essentially written contracts about the future prices of assets?they are, crucially, a promise. pinpoints one crucial feature of derivatives (seen especially in the housing market)?that they function as complicated promises that are used to speculate on the probability of others not keeping their promises?and details how this feature spread like a contagion through the market. With his characteristic clarity, Appadurai explains one of the most complicated aspects of our modern economy, and makes the critical link between the numerical force of money and the linguistic force of what we say we will do with it.