About half of humanity lives in urban environments today and that number will grow to 80% by the middle of this century; North America is already 80% in cities, rising to 90% by 2050. Cities have to be efficient, resilient, and sustainable, and they must address quality of life issues for their citizens. To achieve these goals, one has to understand the various processes and phenomena that determine the functioning of cities. Examples to be addressed in this workshop include climate, traffic, energy and resource conservation. We expect that concepts from statistical physics can take us beyond today’s imperfect and often anecdotal view of cities. Today, new technologies provide opportunities for sensors to acquire a plethora of data with high spatial and temporal resolution, including light, temperature, wind, pollution, traffic flow, and even personal information on location, activity, and physiology. Remote sensing also offers new possibilities.