Given that three such brilliant thinkers, one of whom (McKenna) is my personal intellectual hero, contributed to a single book, I assumed that it was a guaranteed good read. What I failed to consider is the format that such a book requires, and the reason such a format is rarely employed. The trialogue is digressive, unpatterned, and remains relatively surface-level on the issues in question. While there are genuine insights in this book on many subjects, only very few of these felt 'new'. I found that just as things got interesting the subject would change or take a new unsubtle path. The discussion is also unrepentantly speculative. So often do assertions of ideas go by unattended that it is likely that a great number of them would fail under scrutiny. In fairness, I am also certain that many would succeed, and their implications (once someone takes up their ideas and follows the threads to the limit of their applicability) could be phenomenal.
That said, I do highly recommend this book for anyone who does little thinking on these subjects, for whom it could prove an important initiation. Its topics meander between the nature of consciousness, the role of humans in the world, the nature of the 'other' and of ethereal entities, education, spirituality, and so on. I am sure that most would succumb to a spark of interest that would inspire further study into many of these subjects, for which purpose there is both a bibliography and a list of 'books of related interest.'