the Age of Crypto­currency

Paul Vigna and Michael Casey, St Martin's Press, 343 pages, $27.99

For a growing number of geeks and venture capitalists, bitcoin is less a currency than a technology that can be used to transfer money and other assets cheaply and securely.

In "The Age of Cryptocurrency," Paul Vigna and Michael Casey predict that bitcoin's main calling will indeed be as a disruptive payment system. Before cryptocurrency, societies had to rely on banks to keep track of payments and guarantee the financial system. Bitcoin's "blockchain" technology cuts away the middlemen by taking over the role of ledger-keeping. "At its core, cryptocurrency is not about the ups and downs of the digital currency market," the authors write, but "about freeing people from the tyranny of centralized trust."

The book is at its liveliest when it discusses the potential impact of bitcoin. The currency may not be a must-use in countries with well-developed payment services, but it could help the poor world's 2.5 billion unbanked to connect to the formal financial system. What is more, because no one controls the blockchain, it has already become the foundation for a growing number of start-ups. And the technology may also undermine other centralized institutions such as stock markets, or give the sharing economy a boost.

Wisely, Vigna and Casey do not predict that this will happen overnight, or that the technology is a panacea. Cryptocurrencies will continue to grow, they write, not alongside the offline world, but attached to it, with institutions adopting it to suit their needs. Bitcoin may well trigger a revolution, but it will be a slow one.