When your parents were young, people could buy cigarettes and smoke pretty much anywhere — even in hospitals! Ads for cigarettes were all over the place. Today we're more aware about how bad smoking is for our health. Smoking is restricted or banned in almost all public places and cigarette companies are no longer allowed to advertise on TV, radio, and in many magazines.

Almost everyone knows that smoking causes cancer, emphysema, and heart disease; that it can shorten your life by 10 years or more; and that the habit can cost a smoker thousands of dollars a year. So how come people are still lighting up? The answer, in a word, is addiction. Once you start, it's hard to stop.