This book is a terrific reference for anyone interested in religion, mysticism, esoterica, ancient history and any form of Gnosis from ancient to modern. Though it would appear at first glance to be a basic dictionary of words rarely used and seldom contemplated in the average everyday world, it is a storehouse of clues to the origins of Western esoterica and literary fancy. Take "AEEIOUO," an entry on page 5. Reminiscent of the Caterpillar's song in Lewis Carol's "Alice's Adventures in Wonderland" it is also the (Greek) vowels chanted repetitively in certain forms of magic derived from Gnostic texts ... a little online cross-research explains that according to the Nag Hammadi, Aeeiouo is the shape of the Self Begotten Soul. (In Greek, Alice happens to mean "truthful.")
The Nag Hammadi codices are outlined beginning on page 168 where it is explained that the "tractates in the codices are in Coptic, but scholars believe they were originally composed in Greek."
What's a "tractate"? Look it up on page 247 where you can also brush up on the word "transcendence" contrasted with "immanence" on page 124.
A Dictionary of Gnosticism will help you comprehend Plato's Timaeus from which the concept of the "demiurge" originates, as well as modern film concepts. The 1999 movie "The Matrix" is explained on page 156 where "archon" equivalent characters (agents) govern reality "on behalf of the entity that created the world". The demiurge in Gnosticism is compared to the machines in the Matrix.
Try Googling all that! It is wonderful to have this handy Gnostic dictionary at one's fingertips as a quick reference for looking up some of the more obscure terms of Gnosis ("direct spiritual experience") - but it also helps in grasping much of what more mainstream literature and contemporary media have been trying to tell us all along. The truth is in between the lines ... or in the process of "inverse exegesis." Make up your "Nous" or mind and avoid the "interdict" if you are a heretic. Explore Pistis Sophia. Use this quick reference manual of Gnostic terms as a springboard for further inquiry. Ablanathanalba.