This book forms a reasonably good introduction to the ideas of Gnosticism for the general reader. The author begins with a discussion of Simon Magus, said to be the first Gnostic, and how he is portrayed by the heresiologists, mainly Irenaeus. The author largely takes the fashionable position here that the testimony of Irenaeus is inaccurate.
Then we delve somewhat deeper into Gnostic thought through a look at two works from the Nag Hammadi codices, namely The Exegesis of the Soul, and the important Secret Revelation of John.
Subsequently we are taken on a tour of other world views of the time, namely Judaism, Platonism, early Christianity and other mystery religions, as a preliminary to investigation of how these may have influenced Gnosticism, which may be seen as 'thoroughly Hellenized Christianity'.
The author then considers several more prominent persons related to Gnostic groups, and other important Gnostic writings, namely the Gospel of Thomas, Gospel of Philip, Gospel of Truth, Treatise on the Resurrection, and the Hymn of the Pearl (from Acts of Thomas).
Similarities and differences between the concept of "gnosis" as employed by Gnostics and three of the Church Fathers (Clement of Alexandria, Origen and Evagrius Ponticus) are analysed, before a final chapter giving the author's own assessment of Gnosticism. Here he somewhat unconvincingly argues that Gnosticism was not elitist.