This paper proposes that in addition to urban research which seeks to provide answers to policy questions, there is also a need for research which directly addresses the physical and spatial complexity of the built environment itself, and explores any effects it may in itself have on the functioning of the urban system. This type of research reflects the questions architects and urban designers typically ask, rather than those that preoccupy planners. For such research to be effective, the physical complexity variable must be controlled at the level at which real design decisions are made. Space syntax’ research attempts to do this by treating built environments as systems of space, analysing them configurationally", and trying to bring to light their underlying patts and structures. Results from space syntax research into many aspects of urban space and how it works show a consistency which suggests that analysing spacial structure can be a general means of investigating the structure and function of cities. It may, in effect, be the common language of the city.