These are the proceedings of the international symposium on "Experi- mental Respiratory Carcinogenesis and Bioassays", held from 23 to 26 June 1974 at the Battelle Seattle Research Center, Seattle, Wash., USA. Human lung cancer is already very common in industrialized countries, and its incidence is increasing. This increase involves mainly epi- dermoid and small-cell carcinoma. Evidence is accumulating that these tumors are associated with such exogenic factors as automobile exhaust, asbestos, chemicals, cigarette smoke, and radionuclides. These pro- ceedings are concerned with finding the...