Culture, rather than political or economic structures, distinguishes the city from the countryside. According to Georg Simmel, it is the "spiritual life" that makes the metropolis a unique place. Walter Siebel builds on this idea. Today, his central thesis is that two characteristics define urban living: the alleviation of necessary work and the constant encounter with strangers. In his historically and theoretically comprehensive monograph, Siebel paints a detailed picture of this urban culture, traces its ambivalent developments, and argues for the renaissance of the city and its cultural productivity.