Cigarettes are among the most addictive substances of abuse and by far the most deadly. In this country smokers know it and try to stop. Their success has been dramatic but partial and excruciatingly slow, and until recently quite uncoerced by government. Cigarettes and nicotine have characteristics distinct among addictive drugs, and some of these help explain why efforts to quit smoking are so often frustrated. Nicotine itself is the most interesting chemical in the treatment of addiction and, in some forms, can pose a dilemma: compromise by settling for pure nicotine indefinitely, or stay with cigarettes and keep trying to quit. Nicotine is not alone among addictive drugs in becoming increasingly identified with the poorer classes.