Like many other Gnostic texts, the writings in the Books of IEOU were not intended for public distribution or to be simply "read". The material here appears more likely to represent excerpts from texts used in initiatory rituals.
In the original coptic manuscript, several pages of related ritual formulae have been collected together -- these having been probably taken from other separate collections. Interspaced in the text are complex symbolic diagrams listing a variety of the "names of God and the Powers". One might suggest these names were to be used as "mantras", vocalized in ritual recitations. The names listed in these diagrams (which are not "translated" or transliterated into the English text) consist of long strings of vowel sounds which, like the great name "IEOU", were intended to be intoned or chanted. This incantation of the divine names occurs as a technique in other ritual traditions (e.g., the Kabbalah of Abraham Abulafia) for the alteration of consciousness in meditation. It should be remembered that the core of Gnosis is individual experience of the divine realms. The Books of IEOU probably represent notes to rituals used in intiation rituals and meditation directed towards producing altered states of spiritual consciousness.
We have reproduce here some of these diagrams to convey the nature of this book. The coptic names underlined in the illustrations are (as noted above) the "names" which have not been transliterated in the translation -- only the non-underlined words (which can be translated with meaning) are rendered. This is of course highly technical material, and the interested student is refered the to the full text found in Carl Schmidt, The Books of JEU and The Untitled Text in the Bruce Codex (Leiden: E. J. Brill, 1978). The illustration below is from the title page of the Coptic codex.