We are, to use a technical economic term, screwed. The cowboy capitalists had a party with everyone's money and now we're all paying for it. What went wrong? And will we learn our lesson – or just carry on as before, like celebrating surviving a heart attack with a packet of Rothmans? John Lanchester has mastered the finer points of finance so you don't have to. In Whoops! he explains, in language everyone can understand, what really happened – and what on earth we do next.