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 on to the black market. It destroys the links between the brain's two hemispheres; leading first to disorentation 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.