Do political decentralisation and inter state competition favour innovation and growth? There has long been a lively debate surrounding this question, going back to David Hume and Immanuel Kant. This book is a new attempt to test its veracity. The existing literature tends to assume that the beneficial effects of inter state competition have been confined to European history. By contrast, China, India and the Islamic Middle East are regarded as inherently imperial and overcentralised. However, these civilisations have not always been unified politically. In their history, there have been long spells of decentralised rule or inter state competition. The same is true for Japan. If the Hume–Kant hypothesis is correct, it should also apply to those periods. This volume analyses the qualitative and quantitative evidence.