Filled with colourful characters and history, Double Entry takes us from the ancient origins of accounting in Mesopotamia to the frontiers of modern finance. At the heart of the story is double-entry bookkeeping: the first system that allowed merchants to actually measure the worth of their businesses. Luca Pacioli -- monk, mathematician, alchemist, and friend of Leonardo da Vinci -- adapted Arabic mathematics to formulate a system that could work across all trades and nations.

As Jane Gleeson-White reveals, double-entry accounting was nothing short of revolutionary: it fuelled the Renaissance, enabled capitalism to flourish, and created the global economy. Kuznets and Keynes used it to formulate GDP, the measure of a nation's wealth. Yet double-entry accounting has had its failures. With the cost of sudden corporate collapses such as Royal Bank of Scotland and Lehman Brothers, and its disregard of environmental and human factors, the time may have come to rethink it for the twenty-first century.