Why have some countries experience durable economic progress while other countries remain left behind? This basic question has vexed development economists for decades -- and for decades economists have tried to reverse engineer one country's economic successes story to discover a blue print that could be applied elsewhere.   Stefan Dercon, was one of those economists when he had an insight that forever changed his approach to the field of development economics. He explains this insight in his new book: Gambling on Development: Why Some Countries Win and Others Lose. Stefan Dercon is professor of economic policy at the University of Oxford and a former senior official in the UK government, including as the senior economist of the United Kingdom's premier overseas development agency.