Recent developments in the field of occupational asthma research and clinical practice are the topic of this volume. The contribution of occupational exposures to chemical and biological agents to the burden of asthma in adults is clearly described in an overview of the most recent epidemiological data from both general population and industry based studies. Emphasis is put on powerful approaches like the use of apprentices studies, which include young individuals, naive with regard to occupational exposures. Diagnostic criteria for work related and work aggravated asthma are introduced...