He discusses their ritual and medicinal usage, cultural artefacts made from these plants and works of art that either represent or have been inspired by them. The author begins with 168 of the most well-known psychoactives - such as cannabis, datura and papaver - then presents 133 lesser known substances as well as additional plants known as "legal highs"; plants known only from mythological contexts and literature; and plant products that include substances such as ayahuasca, incense and soma. The text is lavishly illustrated with 800 colour photographs - many of which are from the author's extensive fieldwork around the world - showing the people, ceremonies and art related to the ritual use of the world's sacred psychoactives.