The major lesson from the 1990s is that relatively superficial changes in the character of urban life can be associated with up to 75% drops in the crime rate. Crime can drop even if there is no major change in the population, the economy or the schools. Offering the most reliable data available, this book documents the decline in the 1990s in American crime as the longest and largest since World War II. It ranges across both violent and non-violent offenses, all regions, and every demographic. All Americans, whether they live in cities or suburbs, whether rich or poor, are safer today. Casting a critical and unerring eye on current explanations, the book demonstrates that both long-standing theories of crime prevention and recently generated theories fall far short of explaining the drop in the 1990s. A careful study of Canadian crime trends reveals that imprisonment and economic factors may not have played the role in the U.S. crime drop that many have suggested. A combination of factors rather than a single cause produced the decline. It is clear that declines in the crime rate do not require fundamental social or structural change, but that smaller shifts in policy can make large differences. The significant reductions in crime rates, especially in New York, where crime dropped twice the national average, suggests that there is room for other cities to repeat this astounding success.