The Crusades happened almost a thousand years ago—why do they still provoke an argument? Osama bin Laden has used them to attempt to rally the Islamic world to his cause; President Bush has called the war on terrorism a "crusade." But what is the truth about the Crusades? Were they motivated by savage greed and intolerance or by pious idealism? Were they an unprovoked attack by the West on the Islamic world or a reaction to centuries of Islamic incursions? How should we understand the legacy of the Crusades today, in a time of conflict between the West and radical Islamic terrorists?

Study after study has shown that married people are healthier and wealthier than unmarried people and that children raised in two-parent homes are generally more successful in life than those who aren't. And yet, according to the U.S. Census, about half of all first marriages end in divorce. Additionally, since 1960 the percentage of children born out of wedlock has grown from single digits to 20 percent. What is going on? Is the decline in marriage a symptom of underlying cultural problems in modern America? Or is it misguided to focus on marriage rather than on the economic problems facing all low-income families, whether married or not?

Should the U.S. Census stop collecting racial and ethnic data? The 2000 census asked Americans to identify themselves according to 126 possible racial and ethnic categories, up from just 5 categories in 1990. Movements are now afoot to add even more racial categories to the 2010 census. Does the collection of all these data stand in the way of the creation of a truly color-blind society? Should we drop questions of race from the census and other government forms? Or are these data critical tools in the ongoing fight to end inequality and discrimination?

In 1965, Congress voted to change the laws that had restricted immigration into the United States for more than four decades. The Immigration Act of 1965 resulted in a wave of increased immigration that continues today. How do recent immigrant groups compare with those of the last great wave of immigration a century ago? Are they successfully integrating into American culture or threatening America's cultural stability? Should immigration once again be restricted, or should we concern ourselves with helping immigrants assimilate when they arrive?