The Corpus Hermeticum is one of the primary works within the Hermetic Tradition. This Renaissance era craft is nonetheless based upon philosophical materials from far older times, namely the third or fourth century AD, from which the primordial material came.
Credited to Hermes Trismegistus, the Divine Pymander (sometimes spelled "Poemander") touches upon astronomy, science, nature, and a great deal of theological material. It is presented in the form of discourse; a format which will be familiar to anyone also familiar with Plato's "Republic" and some similar philosophical works of antiquity. Through his discourse with several individuals, Trismegistus attempts to draw upon the overarching philosophy "as above, so below."
Thus then, this work describes the very process and ideation behind all of existence, the purpose of life, and the nature of good and evil, all through its treatises upon various topics.