This series of manuals is primarily aimed at project managers, engineers and technicians. However, given the wide range of subjects covered, it is also an important tool for all actors in the sector, ranging from those involved policy development to those constructing systems at village level. The series has clear focus on water supply in rural settings. It proposes technologies with due consideration for socio-cultural, economic, intsitutional and regulatory requirements. This approach is in keeping with the SDC water and sanitation policy, emphasising the balanced development approach leading to sustainable programmes and projects. It should be noted that the present series deals almost exclusively with water supply. The importance of sanitation is however clearly established in Volume 1, which deals predominantly with the software aspects necessary to achieve an impact. It includes some proposals for optional tools, approaches and institutional arrangements and is intended as an overall introduction to the other, more technical, volumes of the series.