When most people think of the Crusades, they have in mind the Third Crusade. The one 
involving Richard the Lionheart, Saladin, and the contest for Jerusalem (ultimately a failed exploit from the Christian side of things), and (less seriously) Sir Walter Scott, Robin Hood, the Merry Men, and so on. And so this new military history about one of the most famous battles of the Third Crusade, The Siege of Acre, 1189-1191: Saladin, Richard the Lionheart, and the Battle that Decided the Third Crusade (Yale UP), by John D. Hosler, looks to be a useful new source on this important conflict.
The two-year-long siege of Acre (1189–1191) was the most significant military engagement of the Third Crusade, attracting armies from across Europe, Syria, Mesopotamia, Egypt, and the Maghreb. Drawing on a balanced selection of Christian and Muslim sources, historian John D. Hosler has written the first book-length account of this hard-won victory for the Crusaders, when England’s Richard the Lionheart and King Philip Augustus of France joined forces to defeat the Egyptian Sultan Saladin. Hosler’s lively and engrossing narrative integrates military, political, and religious themes and developments, offers new perspectives on the generals, and provides a full analysis of the tactical, strategic, organizational, and technological aspects on both sides of the conflict. It is the epic story of a monumental confrontation that was the centerpiece of a Holy War in which many thousands fought and died in the name of Christ or Allah.