During the late 11th through the early 14th centuries at least seven major expeditions were made between Western Europe and the Holy Land with the goal of ending Muslim control of Jerusalem. Ultimately the crusaders were driven out, but not before a cultural exchange had taken place that had an immense impact on Western Europe and an equally enormous, albeit less positive, impact on Arabs and the Islamic world. Although the crusades occurred many centuries ago, echoes still resound through the current clashes of nations and ideologies, kidnappings for ransom, assassinations, and the declaring of 'jihad'_all making the crusades an eminently timely subject. This one-volume overview provides an accessible reference work for scholars, students, and general readers on the period with numerous entries on key persons, places, events, battles and sieges, use of weapons and armor, and the deeper issues of the political and cultural background. Complete with a detailed chronology and a bibliography, this work allows readers to learn how Europe was changed forever by these battles with Islam.