An economist examines three modern forces that have redefined what "money" means, who controls it, and what the future of finance might look like.   Money is increasingly cheap, digital, and mobile. In Money in the Twenty-First Century , economist Richard Holden examines the virtues and risks of low interest rates, mobile money, and cryptocurrencies, and explains how these three elemental forces will continue to play out—in our wallets, on the blockchain, and throughout major economies—in the decades to come.   Holden weaves in the stories of three people who have exerted massive influence over the future of modern money: US treasury secretary Janet Yellen, Ethereum cofounder Vitalik Buterin, and Raghuram Rajan, former governor of the Reserve Bank of India and chief economist at the International Monetary Fund. Moving from micro to macro, Holden investigates the infrastructure that permits digital transactions, the currencies that underpin them, the race for control of those currencies, shifts in policy and the international monetary system, and the impact on our politics of money in the digital age. Ultimately, Money in the Twenty-First Century asks if governments can keep these three tectonic powers of low interest rates, mobile money, and decentralized finance under control. "A layperson's guide to the way in which digital currencies may evolve over the coming decades and what this means for government-issued currency. This is the issue that will confront policy makers. Richard Holden integrates a currently quite disparate and technical literature to translate that research into what it all is likely to mean for the real world."—Joshua Gans, Professor of Strategic Management, University of Toronto, and author of  The Pandemic Information Gap: The Brutal Economics of COVID-19 "Holden has an uncanny knack for writing about complex topics in a lucid, understandable way. He uncovers the reasons behind the recent spate of banking crises and explains where banking is likely to be headed in the era of digitalization. An edifying read for lay and expert alike.”—Bengt Holmstrom, Massachusetts Institute of Technology, 2016 Nobel Laureate in Economics   Richard Holden is Professor of Economics at the University of New South Wales, Sydney.