Psychoactive drugs affect the way the brain carries out its functions. They can stimulate, sedate, produce strange mental pictures, relieve pain, disorient normal ways of thinking, or restore some disoriented ways of thinking to normal. Some of these drugs are among the most beneficial known to medicine; however, some are extremely damaging to the individual and society. Drugs and the Brain explores how and why the human body responds to psychoactive drugs, focusing on the way these substances influence the specific areas of the brain, the body's most complex and fascinating organ.