Our world is governed by the numbers generated by the accounts of nations and corporations. We depend on these numbers to direct our governments, our institutions, corporations, economies, societies. But where did they come from and how did they become so powerful?The answer to these questions begins in the Dark Ages in northern Italy with a new form of record keeping perfected by the merchants of Venice called double-entry bookkeeping. The story of double entry stars a Renaissance monk, mathematician, magician and constant companion of Leonardo da Vinci, his 27-page treatise for merchants, re.