One aim of this book is to demonstrate (father than to merely state) that our modern culture stands out in the long record of human history because of its difficulty in accepting in an orderly and integrated way the role natural substances, primarily from the plant kingdom, have played in aiding mind expansion. This book provides a thorough overview of what is currently known about the ancient use of psychedelic drugs for ritual and spiritual purposes. It offers the interested general reader a useful single source of information on the whole subject area. As part of this inquiry, it is important to evoke some understanding of actual experiences with psychedelic substances A failure to register the experiential qualities of hallucinogens would make it more difficult for us to understand the fascination they have held for human beings throughout all known time. So although the main focus here is on the long human usage of hallucinogenic substances— the Long Trip — we will also hear first-person accounts of those pioneers who have studied the substances in recent and modern times. This book is not a specialized work of ethnobotany, archaeology, anthropology, plant chemistry, or the modern social history of psychedelia It is nevertheless uniquely updated and comprehensive, and provides far more than a superficial study of the overall subject area. I trust that it will provide a worthwhile general reference for a variety of readers. The later sections of the book examine generally overlooked evidence showing that a record of archaic ecstatic experience was written ' on the landscape in various parts of the world. I suspect this material is unfamiliar to most readers. The fact that we have , indeed , been on a Long Trip raises deep questions that humanity needs to address. So profound are these questions that it will take a tremendous effort on the part of the scientific community to explore them adequately.