by Carl Sherman

About the author: Carl Sherman writes on health, medicine, and psychology for national magazines and medical newspapers.

It may not be a “sin” anymore, but few would dispute that smoking is the devil to give up. Of the 46 million Americans who smoke—26 percent of the adult population—an estimated 80 percent would like to stop and one-third try each year. Two to 3 percent of them succeed. “There’s an extraordinarily high rate of relapse among people who want to quit,” says Michael Fiore, M.D., M.P.H., director of the Center for Tobacco Research and Intervention at the University of Wisconsin.

The tenacity of its grip can be matched by few other behaviors, most of which, like snorting cocaine and shooting up heroin, are illegal. Since 1988, nicotine dependence and withdrawal...