In the view of Canadian mathematician David Orrell and Czech-Canadian journalist Roman Chlupatý, money is not just an “inert medium of exchange,” but “something closer to a religion” (p. 2). Without faith in a monetary system, it will collapse. Money is a social convention that has value because society says it has value. In Orrell and Chlupatý’s words, “Money doesn't so much need to be backed as it needs to be used” (p. 218).

The Evolution of Money is a well-written book filled with historical vignettes and anecdotes. The authors relate a compelling historical narrative in which money alternates between a virtual credit regime and a metal-backed regime. In their chartalist view, Money 1.0 began in Mesopotamia as a credit system that kept track of what was owed to whom. Money then was virtually a virtual currency; coins did not arise spontaneously to make barter more efficient. Instead, metal-backed Money 2.0 arose when governments needed mechanisms to pay the troops and control the population. Governments could force the payment of taxes in money objects, which created a demand for those money objects and thus made those money objects useful as a medium of exchange. Money was and is an instrument of state power.

A shortage of metals in the Middle Ages led to Money 3.0, a reversion to a credit system. The plunder of the New World by the conquistadors relieved the shortage of metals and led to Money 4.0, the classical gold standard. We are now in a Money 5.0 epoch, in which currencies like the dollar and euro are mostly virtual and closer to cybercurrencies than many realize.

The authors go beyond the usual descriptions of money by mainstream economists. Indeed, they rightly criticize mainstream economists for ignoring money, currency, and debt in traditional economic models. They cite the assertion that central banks were surprised by the 2008 financial crisis because the banks' dynamic stochastic general equilibrium models contained “neither money nor banks nor debt” (p. 165). Money—“the most important technology”—should be at the center of economic models and not assumed away as it often is (p. 221). Apparently, economists should be even more pious members of the church of money.

The authors delve further into the psychology and sociology of money. They assert less convincingly that “the psychology of money, it seems, has much to do with our attitude toward femininity” (p. 115). Money as a virtual credit system is portrayed as masculine heads and wealth-backed money as feminine tails. Orrell and Chlupatý note that the “switch to coin in the sixteenth century coincided with the peak number of witch hunts in Europe—an extraordinary period of repression that can be seen as a backlash against the growing power of women” (p. 115). While an interesting factoid, the connection is far from clear.

The authors extend their view of the duality of money and draw a yin-yang distinction between price and value. They bring in analogies to quantum physics where one cannot know both the position and the momentum of an object. Even further, they rhapsodize about “money's fragile and uneasy link between objective number and subjective value, reason and emotion, reality and perception, order and chaos, precision and ambiguity; and it is fueled by the same energy—and the same quantum chaos—that binds heads with tails” (p. 164).

The book does not pretend to be a politically neutral academic tome. Rather than a defect, this makes the book not only more entertaining but also more thought provoking. The authors refer to “weaponized” Cold War theories of economics that hold that market economies are better than centrally planned ones and claim, “Economic theory became an intellectual tool of American might” (p. 151).

Of particular interest are the book's descriptions and ruminations about various currency experiments and how money will continue to evolve in the future. These include multiple currency regimes such as the Russian golden chervonet and negative-interest currencies such as the Austrian worgl and the Bavarian wära, along with numerous scrips and local currencies. Air miles and cell phone minutes have also become media of exchange.

Bitcoin and blockchain technology are given ample treatment. In a world where people can store cryptocurrencies in their software wallet and transact directly with a counterparty, banks lose their role as operators of the payment system. Indeed, in an Internet of Things world, things may well start paying by and even for themselves.

The book's concluding chapter, appropriately entitled “Utopia,” makes some predictions about the future evolution of money. Orrell and Chlupatý predict a world with overlapping currencies, but also one where money as we know it will play a smaller role because the Internet will enable different forms of social exchange. However, the authors also consider the big picture and call for a future world order that takes into account environmental sustainability, inequality, and ethics, with new theories of economics “that will put the dualistic, dynamic, and creative properties of money at their heart” (p. 237).