Angela Hull is Professor of Spatial Planning, School of the Built Environment, Heriot-Watt University, Edinburgh, UK. E. R. Alexander is Professor (Emeritus) of Urban Planning, School of Architecture and Urban Planning, University of Wisconsin-Milwaukee, USA, and Principal, Alexander Planning and Design, Tel-Aviv, Israel. Abdul Khakee is Professor Emeritus at the Department of Planning and Environment, Royal Institute of Technology, Stockholm, Sweden. Johan Woltjer is Professor of Regional Planning and Development, Faculty of Spatial Sciences, University of Groningen, Netherlands.