How do smokers evaluate evidence that smoking harms health? Some evidence suggests that smokers overestimate health risks from smoking. This book challenges this conclusion. The authors find that smokers tend to be overly optimistic about their longevity and future health if they quit later in life. Older adults' decisions to quit smoking require personal experience with the serious health impacts associated with smoking. Smokers over fifty revise their risk perceptions only after experiencing a major health shock — such as a heart attack. But less serious symptoms, such as shortness of breath, do not cause changes in perceptions. Waiting for such a jolt to occur is imprudent. The authors show that well-crafted messages about how smoking affects quality of life can greatly affect current perceptions of smoking risks. If smokers are informed of long-term consequences of a disease, and if they are told that quitting can indeed come too late, they are able to evaluate the risks of smoking more accurately, and act accordingly.