He is a most unlikely revolutionary: a middle-aged, middle-class former grammar schoolboy who honed his radicalism on the mean streets of rural Shropshire. Until recently, Jeremy Corbyn was barely known outside political circles, yet last summer he rode a wave of popular enthusiasm to win the Labour Party leadership by a landslide, with a greater mandate than any British political leader before him. When he was first persuaded to run, not even Corbyn himself dreamed he would somehow tap into an unforeseen populist fervour for change. The thought of being leader was initially said to terrify him. So how did this very British iconoclast manage to snatch the leadership of a party he spent forty years rebelling against? Who is he and where did he come from? And what exactly happened over the space of an extraordinary summer to propel an old lefty called Jeremy to inspire and excite hundreds of thousands of people, and breathe new life into the socialist ideals that he, almost alone,...