Once upon a time, over a millennium ago, Central Asia was so vast and forbidding that the cultures on its edge knew almost nothing about it. Wildernesses of desert, mountain and grassland divided east from west. But in around AD 800 it began to open up. During the following centuries, it seethed with rival cultures, religions and empires, all emerging, expanding, sinking and dying like cells in a 6,000-kilometre Petri dish, with many an unforeseeable consequence along the way.

Christoph Baumer’s book, the third in a four-volume series, is a rarity – a labour of love, scholarship and high-class publishing. Like the previous two books, this one is an astounding achievement, tracking the twenty-eight or so dynasties and sub-dynasties that rose and fell in the lands between eastern