THESE Oracles are considered to embody many of the principal features of Chaldæan philosophy. They have come down to us through Greek translations and were held in the greatest esteem throughout antiquity, a sentiment which was shared alike by the early Christian Fathers and the later Platonists.
William Wynn Westcott—who usually published as W. Wynn Westcott or W.W. Westcott and occasionally under the motto Sapere Aude—was a coroner, Theosophist, and Freemason who was a leader in the Societas Rosicruciana in Anglia and went on to co-found the Hermetic Order of the Golden Dawn, later remaining involved with the breakaway group Stella Matutina.
It should be stated upfront that most of the "oracles" that make up this collection are thoroughly Hellenistic and relatively late. That being said, some of the more poetical examples could very possibly go back to a Chaldean and/or Persian provenance.
I must say that reading the introduction to this reminded me of why occultists, like Westcott and his ilk, made very poor scholars. They missed almost no opportunity to speculate uselessly; and more in order to impress others (usually uninformed themselves) with their knowledge of all things occult/esoteric. I thought of something Gershom Scholem said about occult Kabbalah enthusiasts that I thought totally apropos to the reading of Westcott's introduction to the Oracles: "To this category of supreme charlatanism belong the many and widely read books of Eliphas Levi (actually Louis Constant; 1810-1875)… and Frater Perdurabo (Aleister Crowley; 1875-1946), all of whom had an infinitesimal knowledge of Kabbalah that did not prevent them from drawing freely on their imaginations instead."
One can hardly take seriously the sea of pages vomited out by this self-involved clique. One can see how discoveries in the middle of the 20th century even proved their speculations to be idle fantasy. Many of that group said that the Essenes were Kabbalists; and with the discovery of the Dead Sea Scrolls, the world was finally exposed to what Essenic writings looked like and, surprise surprise, nothing even remotely resembling Kabbalah was discovered among the scrolls. One can include a multitude of other ridiculous assertions by theosophists, thelemites, Masons, Rosicrucians, et al. I wouldn't recommend the vast majority of that torpid abyss of pseudo-literature.
While the Chaldean Oracles are important for understanding late Hellenistic philosophy (especially Neo-Platonism), they do not shed much light on Chaldean or Zoroastrian religious thought. As far as Babylonian religious thought is concerned, one should go to Berossus for a more or less reliable late account, and above all, to the vast collections of tablets that have been discovered for an earlier account. For Zoroastrian thought, one should go to the Gathas and the Avesta for the earliest written evidence. The Pahlavi texts are also incredibly interesting, but they are notoriously difficult to date due to constant redaction and interpolation in the process of textual transmission.
Update: I want to add that I am incredibly impressed with Thomas Stanley's treatment of the "Chaldean Philosophy" in his History of Philosophy. It's a far better examination. Although, one must concede that most of the information he provides as being "Chaldean" is really Neo-Platonists interpreting the Oracles and thus simply Neo-Platonism. The Oracles themselves (as indicated by the fragments) are fairly Hellenistic as is, although a bit more poetically ambiguous. It is tempting though to theorize as to how the local religious wisdom traditions influenced Porphyry and Iamblichus. Areas in Syria, and in what is now Lebanon, could have been the beneficiaries of Chaldean religious and wisdom traditions which found it's way into Neo-Platonism through Porphyry and Iamblichus. Stanley provides Psellus' and Pletho's comments on the oracles as well as an assortment of extracts from Neo-Platonist commentaries. Thomas Stanley's work on Chaldean philosophy can be purchased separately, but at a price that makes buying the combined volumes of his History of Philosophy a far better buy.
I really appreciated the large, easy-to-read print in this edition of a classic book on the mysteriously fragmentary Chaldean Oracles, a collection of poetical teachings dating back to at least as far as the 2nd century CE, and perhaps quite earlier than that. These writings exercised a profound influence on Neoplatonism as it was developing from the 3rd century CE onward, and they were highly regarded by some of the greatest minds in late antiquity and the Renaissance (when they were rediscovered in the West). Although each fragment is a bit obscure on its own, the brief comments and notes provided with the English translations of the ancient fragments serve to elucidate and contextualize what each particular passage might have meant to its first readers or hearers, along with what meanings were attached to it by later Neoplatonic commentators. The Chaldean Oracles are indeed mysterious, but perhaps a bit less so, once this book has been read and reflected upon. Highly recommended for those interested in ancient philosophy, cosmology, and comparative religion.