The revision of this Handbook has entailed much time-consuming and meticulous work over the last two years. Many people have offered advice and help, and supplied documents which we have been able to put to good use. The initial stimulus came from a study by A. Oshaug (Oslo) and D. Benbouzid (WHO), and from Dr P. Chastonay of the Institute of Social and Preventive Medicine (Geneva).

Many of the thousands of colleagues who have taken part in workshops with the author of the Handbook have helped by their questions and comments to make this revised edition more relevant to the needs of users. These contributors are too numerous to be mentioned by name.