One murder, one defendant, 12 jurors and a verdict to give: welcome to 12 Angry Men, a cinematic masterpiece that hasn’t aged a day since it was released 60 years ago. Unfolding in a series of arguments and rebuttals, Sidney Lumet’s film serves up a blinding snapshot of decision-making craft, relentlessly prompting us to reflect on the way in which experience, doubt, instinct and rational thought all impact on how decisions are taken. It’s a far cry away from self-help personal development books, but just how deep does it go?