Book excerpt: Stretching from Morocco to China, the Umayyad caliphate based its expansion and success on the doctrine of jihad--armed struggle to claim the whole earth for God's rule, a struggle that had brought much material success for a century but suddenly ground to a halt followed by the collapse of the ruling Umayyad dynasty in 750 CE. The End of the Jihad State demonstrates for the first time that the cause of this collapse came not just from internal conflict, as has been claimed, but from a number of external and concurrent factors that exceeded the caliphate's capacity to respond.