The Islamic militant who killed two people in London last week was supposedly being monitored by the authorities. That revelation has prompted a fierce debate about what went wrong. We take a look at the state of the global AIDS epidemic. And as their country goes to wrack and ruin, Venezuelans have been turning to video games, but not for the reasons you might think. For full access to print, digital and audio editions of The Economist, subscribe here www.economist.com/radiooffer