Despite the subtitle, the "Last Supper" does not loom large in this book, which professes to offer an exegesis of the Naassene teachings disclosed in the fifth chapter of Hippolytus' Refutation of All Heresies. In particular, the significance of the paradigmatic Eucharist is reduced to a demonstration of divine immanence, and this point is accomplished in the first half of the book. Later digressions about grail mysteries and subtle human anatomy do not add markedly to this understanding.

On the whole, the book is entertainingly wide-ranging and makes decent use of its sources. These run from very mainstream works in biblical source criticism and the history of Gnosticism to a mix of provocative and "alternative" writings like those of Graham Hancock, Peter Tompkins, and Elizabeth Clare Prophet. Author Gaffney's relationship to Jungianism is a little peculiar, in that he professes to be "a Jungian," and yet he thinks that the psychologist is being "dismissive" when Jung characterizes Gnostic doctrines as deriving "from the unconscious" (142-3), which surely shows a misunderstanding of Jung, whatever Gaffney's appreciation of Gnosticism. The historical value of this book is chiefly limited by Gaffney's axiomatic acceptance of the empirical reality of the savior god "Jesus Christ" as a historical human being and his reluctance to compare primitive Christianity to the other ("pagan") mysteries of late antiquity. The latter of these faults is especially galling in light of the extent to which this issue is raised explicitly in the text of Hippolytus that the book uses for its touchstone.

Gaffney includes as an appendix the text of "The Naassene Sermon" from Hippolytus, in an edition that he has composited from the translations of Birdsall, MacMahon, and Legge, with interpretive influence from G.R.S. Mead. It is valuable to include this material for reference, but some of the editorial choices are questionable. In particular, Gaffney retains the source notations introduced by Mead to distinguish a pagan syncretist source (S), a Jewish mystical commentator (J), the Naassene Christian scribe (C), and the heresiological anthologist Hippolytus (H). Gaffney rightly questions the value of dividing J and C, yet he not only keeps these ubiquitous symbols, but does so as simple in-line capital letters that are ubiquitous throughout the text, impairing its readability. (The letters could have been superscripted, or better yet, omitted, with italics used for H passages and underscores for S.)

Gaffney's eventual position in this book is one that fits comfortably within the range of post-Theosophical occultism, complete with invocations of Vedic mysticism. For this latter topic, he is conspicuously reliant on the 1980 volume Layayoga by Shyam Sundar Goswami, albeit with a well-articulated appreciation of the Western reception of this tradition since the 19th century. Other than a general affinity for "New Age" ideas, this Gnostic Secrets book represents no coherent neo-Gnostic school. The aspects of the book I found most novel and interesting involved the study of hydraulic Hebrew mysticism: a set of tropes regarding the magical manipulation of rivers and other waters throughout various biblical texts and related traditions, viewed in terms of mystical attainment. While I don't endorse all of its conclusions, I appreciate its spirit, and I think it is an engaging and helpful excursion for readers investigating the re-interpretation of Christian origins and Gnostic mysticism.