Guardian journalist Jon Ronson's Them began as a book about different kinds of extremists, but after Jon had got to know some of them - Islamic fundamentalists, neo-Nazis, Ku Klux Klansmen - he found that they had one oddly similar belief: that a tiny, shadowy elite rule the world from a secret room . . .

In Them, Jon sets out, with the help of the extremists, to locate that room. The journey is as creepy as it is comic, and along the way Jon is chased by men in dark glasses, unmasked as a Jew in the middle of a Jihad training camp, and witnesses international CEOs and politicians participate in a bizarre pagan ritual in the forests of northern California. Them is a fascinating and entertaining exploration of extremism, in which Jon learns some alarming things about the looking-glass world of 'them' and 'us'.

Are the extremists on to something? Or has Jon become one of them?