IT IS AGAINST THE LAW in the United States to sell illegal drugs or to sell legal drugs illegally. Yet drug sales are booming, and despite intensive efforts by government officials and private citizens' groups, drug trafficking has increased in the last four decades. The term drug trafficking covers cultivating, refining, transporting, and selling illegal drugs. Although the drug trade is mostly hidden, or underground, it has had a major impact on the economies of the United States and the world.

The drug sales pyramid

Drug sales of the three major illegal drugs consumed in the United States—heroin, marijuana, and cocaine—can be seen as a pyramid. At the bottom there are teen-aged and adult users who sell or sometimes give drugs away to turn on their friends. Above them on the pyramid are smalltime street dealers, called pushers...