Creating the urban design is a vital stage in any urban development process. From the point of view of sustainable urban development, it is through the design of urban space that many of the intentions of sustainability will be realised. However, design is a notoriously difficult activity to understand, and assessing design is fraught with problems. The design of urban space is a major output of modern economies and has significant impacts on the environment. If the results of urban design decisions are not understood and controlled more effectively than they have been so far, the quality of life available to citizens will continue to deteriorate. Having adopted the PICABUE objectives, environmentalism, futurity, equity and participation (which are considered in more detail in Chapters 1 and 2), and when developing the BEQUEST framework, members of the network have also had to think carefully about the actors who are involved in urban design processes (outlined in the ATEQUE model also discussed in other chapters) and about the criteria they could use in addressing design decisions. These considerations are being carried forward by the members of the network, and the work of proposing detailed protocols for use by urban designers has begun. This chapter presents the state of the art for urban design, and readers should understand that the ideas reported here remain under review. Later volumes in this series of books will no doubt give them further consideration.