For the first time in history, the population of cities exceeds that of the surrounding suburbs and countryside. New York City, after decades of population decline, has recently exceeded its peak 1970s population and continues to grow. Such growth, mirrored in older and newer cities globally, is countered by cities with shrinking populations in the United States and abroad. Both expanding and shrinking cities present new challenges that require preservationists to think broadly and collaboratively, themes that will be highlighted at APT NYC 2013.