The Sackler family is one of the richest in the world, and their name adorns the walls of many famous institutions - Harvard; the Metropolitan Museum of Art; Oxford; the Louvre. The source of the family fortune was vague, until it emerged that the Sacklers were responsible for making and marketing Oxycontin, a blockbuster painkiller that was a catalyst for the opioid crisis - an international epidemic of drug addiction which has killed nearly half a million people.