Since the first skyscraper was erected over a century ago, tall buildings have intrigued people everywhere. Today, they are so commonplace that it is difficult to imagine the modern landscape without them. But skyscrapers are more than icons of the twentieth century; they continue to evolve and fulfill the rapidly changing technological, spatial, and aesthetic needs of the contemporary urban landscape and culture. This volume explores how the genre is being redefined for the twenty-first century, by presenting a critical review of the current state of tall buildings, discussing up-to-the-minute structural inventions, programmatic innovations as well as social, urban, and ecological implications.