One of the great historians of our age asks: how far can a single leader alter the course of history?

The modern era saw the emergence of individuals who had command over a terrifying array of instruments of control, persuasion and death. Whole societies were re-shaped and wars fought, often with a merciless contempt for the most basic norms. At the summit of these societies were leaders whose personalities had somehow given them the ability to do whatever they wished.

Ian Kershaw's new book ...