Although we assume a natural right to privacy, we readily give it away on our mobile phones and on social media websites. So as technology alters the very definition of what privacy is and the science of surveillance becomes ever more acute, is the idea of privacy little more than a quaint last-century notion? Mike Williams traces its history, and ponders what a society without privacy might look like.

(Image: Girls peer through a crack in the door. Credit: AFP/Getty Images)