Money is changing, and this book looks at where the technology of money might be taking us in the future. Technology has moved our concept of money from physical things, to unseen bits of information. With the arrival of smart cards, mobile phones and Bitcoin, it has become easier than ever to create new forms of money. Crucially, money is also inextricably connected with our identities. Your card or phone can identify you for security - and also enable information about you to be associated with your money (think for example of store 'points' cards). To understand all of this and to see where we might be going, the author first of all looks back over the whole history of money, which spans thousands of years. He sees evidence for possible futures in the past, both recent and ancient. After all, not all 'future' starts from today. For example, it can be argued that the future of money began back in 1971, when money became a claim backed by reputation rather than by commodities of any kind. At this point, money became bits. Looking much further back to a world before cash and central banks we see multiple 'currencies' operating at the level of communities, and the use of barter.The newest technologies will take money back to where it came from: a substitute for memory, to record mutual debt obligations within multiple overlapping communities. This time though money will be smart. It will be money that reflects the values of the communities that produced it. Future money will know where it has been, who has been using it and what they have been using it for.