The research connects DMT with the pineal gland and the esoteric belief that the pineal, connected as it is with the crown or sahasrara chakra, eases the spirit’s movement into different states of consciousness or different dimensions of existence. It is clear from the book that further DMT research could lead to major progress in the study of consciousness.

Part One deals with psychedelic substances in science and society, describes the chemical qualities and molecular structure of DMT and discusses the pineal gland and its role in the psychedelic experience. Part Two relates the history of the author’s research, from the actual research proposal and the process of obtaining permission; this section may be skipped by the average reader.

Part Three describes the process of selecting volunteers, obtaining DMT and the first experiments, whilst Part Four details the case reports: what the volunteers said and did, their behaviour, etc. This makes for strange and fascinating reading. Some experiences were positive and illuminating like genuine mystical experiences obtained during meditation, others were eerie or deeply unpleasant.

Pat Five takes stock of the experiences and considers the question of whether it was worth it for each individual. There is an attempt to determine the ultimate benefit derived from the experience for the individual concerned. Definitions come into play but it seems to me that the experiments did benefit each individual in some or other way.

Part Six is a very interesting discussion of the psyche and different states of consciousness. It would seem that spontaneously occurring psychedelic experiences are mediated by elevated levels of endogenous DMT. This spiritual molecule thus provides access to unknown parts of the psyche. If the analogy of brain as receiver may be used, the substance finetunes the brain so that the individual consciousness moves beyond familiar awareness into invisible realms, most of which are inhabited.

There is a difference between this expanded awareness and normal dreaming and the current psychological methods do not satisfactorily explain the phenomenon or the peculiar experiences, especiall as regards the entities encountered. This leads to a speculative discussion on cosmology, the possibility of parallel universes, a multiverse and dark matter, with reference to David Deutsch’s book The Fabric Of Reality.

The author concludes this brilliant work with a discussion on the practical use of psychedelics as therapy, to stimulate creativity or as entheogens. In this regard I would like to recommend Huston Smith’s Cleansing The Doors Of Perception: The Religious Significance of Entheogentic Plants and Chemicals, William James’ Varieties Of Religious Experience, Stephan Hoeller’s The Gnostic Jung And The Seven Sermons To The Dead and the book Chaos, Creativity and Cosmic Consciousness by Abraham, McKenna and Sheldrake.

The book is both written and arranged in an easy-to-handle manner, and I found it highly readable. The experiences documented are fascinating, and much of Strassman's commentary about them is interesting and insightful.

My only reservation is that some of the ideas he presents are initially pure speculation, by the next page have turned into a fundamental assumption on which other speculations may be based, and for the rest of the book appear as solid fact.
This is true of the central theme, that DMT is the "spirit molecule", somehow representing or intimately connected with human spiritual experience. Strassman misses a couple of opportunities to make his case more robustly, I feel. But that doesn't mean he's wrong, and it doesn't negate the overall value of the book.