Population loss is a defining characteristic of most postindustrial cities. Philadelphia lost half a million residents in the last half of the twentieth century, 27 percent of its 1950 population. Camden lost nearly 45,000 residents during this period, a drop of about 46 percent. But the population of Allentown, Pennsylvania’s third largest city, remained relatively stable, varying from as low as 104,000 to as high as 110,000. The difference between Allentown’s 1950 and 2000 populations (106,756 and 106,632) was a hundred-plus people.