4The theory of the universe by Andrew Jackson Davis is filled with arcane and esoteric knowledge, which he says was imparted by spirits he contacted while in entranced clairvoyance. This edition is complete, containing all three volumes of Davis's work.

Davis relays words gained from a series of revelatory encounters he had with spirits from the beyond. In order to compose its contents, he held a total of 157 sittings, each spanning between 3 and 4 hours. Every session saw him lapse into a trancelike state, and dictate to his transcriber what the spirits were telling him. Having always claimed to be of little education, the transcribing process revealed an eloquence and vocabulary far beyond what Davis had apparently learned in life.

At some 335,000 words in length and spread over three principle parts, The Principles of Nature tackles the very nature of reality, time and existence. Aspects of religious, spiritual, philosophical and scientific thought are drawn upon in this enormous treatise, which covers a staggeringly eclectic group of topics. Christianity's development before and after the reign of Constantine, the spiritual activities in the Gospels and other holy lore, and the importance of prophecies are but a few of subjects touched upon.

The final part is more social in tone, commenting on the organization of human society. Davis writes disapprovingly of the poverty and ignorance under which humanity lives, but praises the poor for being the productive yolk of humanity. He claims that with enough careful development, humankind can attain a social model more in key with the harmonious motion of the astronomical bodies.

At the time he published this book, Davis found it attacked by numerous scholars who derided its contents. The scientific claims in particular are shown to contain crude errors and badly understood or obsolete theories. The author responded by reiterating his claim that he had hitherto read only a single book in his entire lifetime, and that The Principles of Nature should be considered a work of fiction.

Proponents of the text however claim that it reveals many ineffable truths about reality, the universe, personhood and the spiritual beings that inhabit realms beyond our own.