They bypass the elites and cut out the gatekeepers. Unlike traditional money they're peer-to-peer, they don't have a nationality, they're digital and democratic. They are also lawless.

For the Afghani woman denied a bank account by a repressive society, or any of the world's 2.5 billion unbanked individuals, cryptocurrencies open new possibilities. What would a world without banks or credit cards or even national currencies look like for all of us?

From Silicon Valley to the streets of Beijing, this is a book about a revolution in the making, a story of human invention, and a guide to the future.