The seventeenth-century philosopher-statesman Francis Bacon famously declared that nothing had changed the world more profoundly than three great inventions: gunpowder, printing and the compass. What he didn't know was that the Chinese had been successfully using all three, long before the west ever 'invented' them. And yet it was another 300 years before a remarkable man called Joseph Needham embarked on his epic, lifetime's work which would finally set the record straight.