Dr. Hoover: Epidemiology is an opportunistic science. It goes where the action is not only in terms of disease and exposure, but also where the tools are. Many epidemiologists are most anxious to use the new molecular tools to assess exposures better, as well as measuring susceptibility. For example, it would be wonderful to have a biological dosimeter for your exposure to benzene from gasoline fumes, or your lifetime level of consumption of fat in your diet. It's difficult to get at these kinds of exposures by asking questions. We are hopeful that the emerging technology from measurement science will provide opportunities in this area. That is an area all of us hope will come to fruition.