For millennia much of the world was ruled by emperors: a handful of individuals claimed no limit to the lands they could rule over and no limit to their authority. They operated beyond normal human constraint and indeed often claimed a superhuman or divine authority. In practice they ran the gamut from being some of the most remarkable men who ever lived, to being some of the worst and least remarkable. Dominic Lieven's marvellous new book is the first to grapple seriously with this extraordinary phenomenon. The entire breadth of extreme human behaviour is here - from warlords to patrons of the arts, from political genius to feeble incapacity and pathological violence. As one of the great experts both on empires and on Russian history, Lieven is brilliantly qualified to write a book that brings to life a system of rule that dominated most of human history, as well as some of history's grandest and most dismaying figures.