A brilliant sci-fi novel from one of the last century's most influential pop culture figures.

Substance D - otherwise known as Death - is the most dangerous drug ever to find its way onto the black market. It destroys the links between the brain's two hemispheres, leading first to disorientation and then to complete and irreversible brain damage.

Bob Arctor, undercover narcotics agent, is trying to find a lead to the source of supply, but to pass as an addict he must become a user and soon, without knowing what is happening to him, he is as dependent as any of the addicts he is monitoring.