Review: The need for a more sophisticated analysis of urban areas is becoming increasingly obvious. Although urban impact upon the environment has been increasing we can no longer assume that action by elected Government is either possible/practicable or sensible. It is in this context that this book is reviewed here: for a more reasoned examination of ecological and environmental issues we need to focus on those key areas which, although outside our traditional subject boundaries, may impinge upon them.

This book results from a pan-European study called POLYNET. The aim was to explore the ways in which European urban areas were connected. There was the initial idea that connections were being made on a number of levels - some supra-national - that would have serious implications for urban governance. To this end, a team of researchers examined a range of measures which together would hopefully better understand the new phenomenon of the polycentric city. Put simply, these are areas dominated by one city but with a range of other urban areas connected to it and acting as a series of centres. Thus the single, national city for researchers such as Christaller becomes a cluster of cites. Above this would be yet another level - the linking of 'world cities' in a supra-national entity sustained by a global elite. Were this true, it would have serious implications for governance and environmental action. To assess the accuracy of this hypothesis, the POLYNET team carried out the research reported here, dividing their findings into 5 parts. The first part - a single chapter - acts as an introduction to the research and the hypotheses being tested. Part two tackles some of the more important technical issues in defining the areas to research and some of the parameters to be measured. It becomes clear from the outset that defining the areas is far from simple (chapter two) and that far from using the built environment, social/economic linkages would better serve the cause (chapter three). At the heart of the mega-region is the idea of the flow of information and people (referred to in terms of Castell's 'space of flows' (chapters four and five). Part three focusses in grater detail of what is going to be measured and how. Here, the methods are laid bare and the assumptions are discussed. Although the concept seems simple, it is very obvious that getting comprehensive data is anything but. There are numerous problems from privacy to commercial security and often, a proxy measure seems the best way forward. These three chapters, six to eight, catalogue the discussions and put forward a reasoned case for the measures taken. In the 8 chapters that comprise part four, each polycentric region is described, key features given and the results of the analysis are discussed. Each region shows a different facet of the polycentric concept. There is some agreement but not the well focussed alignment that one might have hoped. Part five finishes the book as it began, with a single chapter. Here are the main conclusions - the idea of diversity but with some overarching pattern. There's a chance to revisit each region in its own merit and see what each has contributed to the polycentric thesis. In part because this is an EU-funded venture, there's an opportunity to see how these ideas might inform EU regional policy. Finally, it's made very clear that this is just the first part of the idea for an expanded research programme. There have been advances made but several issues, theoretical and practical, need to be addressed before we have more definite ideas.

Overall, this is a fascinating read. It charts the start of what could well turn out to be a major urban research agenda. As such it is not easy to grasp - this is definitely one for specialists who already know much of the field as there is little in the way of basic explanation of key concepts. However, it does show what can be measured and what conclusions can be drawn. It also gives us a glimpse into what appears to be a developing form of organisation and governance that could have profound implications in many aspects of our lives. An essential text for those in urban research.