A hallucinogen can change the way a person sees and interprets reality. There are two types of hallucinogens: natural and synthetic. Natural hallucinogens include some types of mushrooms and peyote, and marijuana. Synthetic hallucinogens include LSD, PCP, and so-called designer drugs such as MDMA (ecstasy). Readers learn about the reasons people use hallucinogens, about the effects on the brain and body, and about abuse, treatment, and recovery. Drug laws and legal issues are discussed, as well as the impact of hallucinogen abuse on society.