This book introduces the reader to cryptocurrencies and blockchain technology. It focuses on Bitcoin, the most popular cryptocurrency, but discusses others such as Ethereum and even includes a short discussion of Libra, Facebook's recently announced crypto offering. Unlike other books on blockchain, which tend to approach the topic from a computer science perspective, this book starts with a monetary theory perspective, describing what role money serves in society, and how Bitcoin relates to and is different from traditional currency. The book then explores the technical aspects of the Bitcoin system: its communications protocol, its decentralized validation processes, and the basics of Bitcoin mining. The book also addresses the challenges that Bitcoin and other cryptocurrencies face: price volatility, adoption/scalability, regulatory uncertainty, and energy consumption. Some central banks are considering issuing their own digital currencies, and the authors discuss several possibilities related to central bank digital currencies. The authors also briefly discuss non-monetary applications of blockchain technology like smart contracts. There are a handful of courses on bitcoin and blockchain in economics programs, for which this could be a suitable primary text, but I think the greater likelihood is for this to be a supplemental text in an economics course geared towards monetary theory and policy, of which Bitcoin and cryptocurrencies would be a smaller unit. The book is accessible enough for undergraduates to understand, but could also be used in Master's or first-year PhD courses. Basically, in economics, the course this book would be used in is required, but the book itself is more of a supplement. The technological details of how Bitcoin works are accessible enough for non-computer science students to understand, but may be a bit lacking for CS majors. However, CS instructors who want their students to understand the economic underpinnings of cryptocurrencies might assign selections from this book