The Mongol invasions in the first half of the thirteenth century led to profound and shattering changes to the historical trajectory of Islamic West Asia. As this new volume in The Idea of Iran series suggests, sudden conquest from the east was preceded by events closer to home which laid the groundwork for the later Mongol success. In the mid-twelfth century the Seljuq empire rapidly unravelled, its vast provinces fragmenting into a patchwork of...