Providing a map to one of the most exciting and emerging areas in contemporary thought, The Psychedelics Manual provides a comprehensive exploration of the why, how and when psychedelics can change lives. This menu of theories from the history of ideas, religious ideas, therapeutic potentials and cutting-edge science allows the reader to experience psychedelic theory from every possible angle. The book explores and illustrates metaphysical systems such as physicalism (the view that everything is made of matter), dualism (that mind and matter are separate substances), idealism (that the world we perceive is projected by the mind), neutral monism (that mind and matter are both expressions of more fundamental stuff), transcendentalism (that there is a type of existence beyond mind and matter), panpsychism (that all entities have some form of consciousness), and pantheism (that Nature is God). In addition to these metaphysical systems, the book also explores metaphysical phenomena such as time, space, qualia and causation.

In an attempt to underpin the experience of living in altered states from a philosophical, psychological and therapeutic point of view, Peter Sjöstedt-Hughes provides a 'way in' to the language and theory of metaphysical experience. Ultimately, he argues that psychedelics give a person a new take on reality, a way of fathoming experience that can help make sense of human experience.