I gratefully acknowledge research support from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), grant number R01 HD027638; the Centre for Economic Policy Research (CEPR) and the Department for International Development (DFID) under grant MRG002_1255; and funding assistance for the continuation of the field surveys by the Thailand Research Fund, the Bank of Thailand, and the University of Thai Chamber of Commerce. I also am grateful for the collaborations with the Federal Reserve Banks of New York, Boston, and Chicago; Lightnet for its decentralized settlement banking network; and EvryNet for the decentralized custodian banking network in Thailand. The views expressed are my own. Thank you to Ernst-Ludwig von Thadden, James McAndrews, discussants of this work, and other participants at the Sveriges Riksbank Annual Macroprudential Conference in June 2017; participants at the Kellogg Conference on Development Economics at Northwestern University in September 2018; participants at the Cryptocurrencies and Blockchains Conference at the Becker Friedman Institute in November 2018; participants at the First New York Fed Conference on FinTech, March 2019; participants at the Penn State Conference in Celebration of Neil Wallace’s Contribution to Economics, April 2019; Daniel Aronoff, Neha Narula, Neil Wallace, Joshua Gans, and Jesus Fernandez-Villaverde for their very helpful comments; and Deborah Jamiol, Jennifer Roche, and Emily Gallagher for wonderful editing. Thank you also for comments on preliminary drafts to Marios Angeletos, Pablo Aznar, Zach Chao, Co-Pierre Georg, Michael Lee, Rhys Lindmark, Jacky Mallett, Antoine Martin, Nish Patel, and Nicolas Zhang. The reviewers for MIT Press made substantive contributions.