The Damietta Crusade, which is often referred to as the 'Fifth Crusade', was the first of the numbered crusades to be targeted against Egypt. Rather than directly targeting Jerusalem, its architects believed that by threatening the economic hub of Cairo the Ayyubid sultan would gladly give up Jerusalem in exchange. Here Laurence Marvin offers the first book-length treatment of the Damietta Crusade in almost 40 years. Written in accessible language and driven by a narrative and analysis firmly grounded in the primary sources in multiple languages, Marvin emphasizes what made this campaign unique, from its planning, choice of target, "brown-water" or amphibious nature, course, and result. He presents a multi-sided perspective by amply describing and analyzing the Egyptians and other groups in the eastern Mediterranean who played an important role in mounting a successful defense against Latin Christian forces. Marvin contends that the crusade in Egypt failed not because it derived from an unachievable or flawed grand strategy, but because of shifting operational goals, leadership issues, the social dynamics within the army, arrivals and departures of participants, and the effective defense led by Egypt's sultan, al-Kamil. This detailed analysis of an understudied event of thirteenth century history brings the latest methodologies of military history to bear on a wide range of primary sources, raising important questions about the complex nature of warfare and crusade in the medieval Mediterranean.