Technology now affects almost every aspect of Water Supply Management, Operation, Planning and Design; the speed of development means that assessing what is "new" is sometimes difficult. Old ideas can now be applied because of new technology; technology is now revealing problems that were unnoticed 10 years ago. Some emerging technologies promise much but are still underdeveloped for use in real world conditions, while we should always remember that "new" technology depends upon the state of development in respective countries, a point which is particularly relevant to the NATO Advanced Study Institute, for which this book has been produced. Thus our objective in producing the book has been to highlight, in a wide range of technical areas, where and how technology is being applied, what is "new" and what the limitations of these technologies are in the real world. We have also tried to provide an European and American perspective where possible to illustrate how problems are tackled in different cultural environments. It is probably true that "technology" is also somewhat dependent upon the political, economic and organisational climate in different countries and we have included a chapter covering these aspects.