Book excerpt: Crusading fervor gripped Europe for more than 200 years, creating one of the most extraordinary episodes in world history. But were the Crusades the first steps in European colonialism, an attempt at ethnic cleansing, a manifestation of religious zeal--or all three? Bringing together issues of colonialism, cultural exchange, and economic exploitation, scholar Christopher Tyerman challenges our assumptions about the Crusades and encourages us to re-evaluate the relationship between past and present.