The eight papers included in this volume attempt to address a number of current urban modeling issues. Some contributions focus on problems found on the interface between urban planning and urban modeling, while others propose more efficient computational algorithms. Still other papers take a critical view on methods and approaches which have so far been dominant in the field. On the substantive side, the topics vary from urban transportation systems to housing allocation, the urban environment and general planning theory. The diversity of topics represents an essential condition for further progress to be achieved in urban modeling.