Sometimes the best intentions can have the worst results: In 1908, British reformers banned the export of Indian opium to China. As a result, the world price of opium soared to a new high and a century of lucrative drug smuggling began, spreading illegal narcotics throughout the British Empire. Digging deep into colonial archives, Tim Newark tells of the epic but little-known story of the battle between law enforcement and these cartels. Among many colorful figures, Newark introduces fanatical American drug-buster Harry J. Anslinger, Shanghai underworld master criminal Du Yue-sheng, and tough North-West Frontier police chief Lieutenant Colonel Roos-Keppel, nemesis of Afghan criminal gangs.