When electronic cigarettes came to the U.S. about 2007, I was skeptical. My assumption was they were a ploy by the tobacco industry to hook more people into smoking under the guise of being a safer product—the notorious low-tar cigarette scam all over again. But as I talked to many e-cigarette users, known as “vapers,” conducted research (Journal of Public Health Policy, 2011) and reviewed a growing body of scientific evidence, I became convinced that e-cigarettes have dramatic potential for reducing disease and death caused by smoking.

Yet...