The fall of the crusader-controlled city of Acre to the Muslims in 1291 inspired many schemes for crusades to recover Jerusalem and its environs. One of these proposals is "How to Defeat the Saracens, " written around 1317 by William of Adam, a Dominican who traveled extensively in the eastern Mediterranean, Persia, and parts of India. The treatise, poorly known even among specialists, presents a five-pronged plan for retaking the Holy Land. In particular, it focuses on cutting off economic and military support for Egypt. William s personal experience in the lands he describes comes through,...