A US technology firm is hoping to make a very old idea finally work by launching self-heating drinks cans. HeatGenie recently received US$6m to bring their can design to market in 2018, more than 15 years after Nestle abandoned a similar idea. Yet the principles behind the technology go back much further to 1897, when Russian engineer Yevgeny Fedorov invented the first self-heating can. So how do these cans work, why no one has managed to make them a success, and what’s HeatGenie’s new approach? To answer that, we have to go back to World War II.