1.1 Organisation and aims This International Seminar, organised jointly by the Com­ mission of the European Communities and the United States authorities (Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health) has brought together more than 150 participants from the Member States of the European Community, from the United States, and also from Greece, Finland, Sweden and Switzer­ land. The aim of the Seminar was to examine the roles of ambient and biological monitoring in protecting the health of workers exposed to toxic agents and to define a multidisciplinary approach to this monitoring. To achieve this aim expertise from the following disciplines, directly or indirectly involved with monitoring, was called upon: medicine, industrial hygiene, nursing, biology, engi­ neering, chemistry, epidemiology, statistics, economics and jurisprudence, and representatives from trade unions, indus­ try and government agencies. The difference in concepts that each of these disciplines has of monitoring and of its role in the team is fully reflected in the papers. 1.2 Current trends in occupational health and hygiene (as related to monitoring).