This volume presents results from three large, more contemporary prospective mortality studies and provides longer followup for two of the older studies dating from the 1950's. When observations from the more contemporary studies are compared with those from the 1950's, one important but disturbing conclusion is apparent - mortality risks among continuing smokers, both males and females, have increased. In fact, relative risks for smokers compared to never-smokers have increased for all major smoking-related diseases - coronary heart disease (CHD), lung cancer, other smoking-related cancers, stroke, and chronic obstructive pulmonary disease (COPD). This increase over time in the relative risks for smokers compared to never-smokers has occured despite a dramatic decline in cardiovascular disease (CVD) death rates in the U.S. population, suggesting that the decline in CVD death rates has been proportionately greater among never-smokers than among continuing smokers. The clearest message that is drawn from the enormous quantity of data presented in this monograph is that smoking prevention and cessation efforts are complementary, not alternative, solutions to the current epidemic of diseases caused by smoking.