The advent of new digital currencies has challenged our notions about money, its function and purpose, and our faith in the financial and banking structures that underpin its legitimacy. Oonagh McDonald charts the spectacular rise of cryptocurrencies over the past decade and considers the opportunities and threats that cryptocurrencies pose to existing fiat currencies. This revised edition includes a new chapter dealing with the high-profile bankruptcies of the recent "crypto winter". The book considers how regulatory bodies have been slow to respond to a technology that is evading existing regulatory frameworks. Urgent and more robust protection is needed from fraudulent initial coin offerings, scams and hacks. Throughout her analysis, McDonald shows that trust is fundamental to the operation of finance and that this will ultimately protect commercial bank money from the threat of new digital currencies. The book offers readers an insightful appraisal of the future of money and the challenges facing regulatory bodies.