Tobacco usage is the major known etiological factor in the causation of human cancer in the U.S.A. and other developed nations. Recent advances in analytical techniques including postlabelling techniques of metabolites, radioimmunoassays for DNA-adducts and determination of hemin-adducts of environmental carcinogens should allow direct assessment in humans of the risk factors and specific effects of tobacco carcinogens. Such evidence is of potentially great significance in verifying long-standing epidemiological and animal studies assessing tobacco and its carcinogens and in advancing and understanding of molecular and cellular mechanisms underlying the neoplastic process. The purpose of the proposed Banbury Center conference, 'New Aspects of Tobacco Carcinogenesis,' is to bring together scientists actively engaged in tobacco carcinogenesis with researchers in molecular biology and biochemistry who are engaged in key work on carcinogen-DNA adducts and cytogenetic lesions and host factors which may influence susceptibility. At the same time, tobacco carcinogenesis and its special aspects will be brought closer to the attention of those research disciplines which are shaping current directions in cancer research approaches. Involvement of molecular biologists and epidemiologists in the research areas dealing with carcinogenic and cocarcinogenic effects of tobacco products should lead to new impulses for studying chemical carcinogens and chemoprevention in addition to better delineating the specific processes involved in tobacco carcinogenesis. The meeting is to be kept small, facilitating and promoting exchanges between the diverse scientific backgrounds represented. The proceedings will be made available to a wider audience through publication of the formal papers together with the edited discussion sessions as Banbury Report 23. In keeping with prior experience in this series, this publication should be available within eight months of the meeting date.