This book is an in-depth study of Tarot symbolism that explores the Arcana's mythology and how it relates to the phenomenon of precession and the Secret Doctrine of Aeonic succession. Much of the symbolism is shown to have been derived from ancient Egyptian, Celtic, Hellenistic, and medieval customs, rituals, and myths, which are traced at least as far back as the Age of Taurus (c. 4200-2100 BCE).

The annual flooding of the Nile River, and its connection to the star Sirius was of paramount importance to the equatorial cultures of this era, and it is demonstrated how much of the mythology and symbolism of later Ages are derived from this fundamental mythos - in which the Mother Goddess was revered rather than vilified, as the case has subsequently become during the Ages of Aries and Pisces.

The ancient Egyptians were quite aware of the phenomenon of precession well before it was "discovered" by the Greek astronomer Hipparchus during the Hellenistic era. Plato recounts how the Egyptian priests of the 7th century BCE maintained that they had knowledge of multiple precessional cycles, and the concomitant periodic destruction of humanity through various celestial cataclysms. Ancient Hindu knowledge of this cycle led to the development of the Yuga concept, wherein each Yuga represents a portion of the Great Year with unique celestial characteristics that influence the relative level of humanity's spiritual advancement.

The structural components of the celestial sphere are shown to be keys to unlocking much of the symbolism behind various esoteric constructs and symbols, such as the Kabbalistic Tree of Life, Yggdrasil, the Enneagram, the Great Seal of the United States, and the Porta Alchemica. These keys are then applied to the Major Arcana in a multifaceted approach that considers astromythology, equinoctial precession, and ancient modes of chronometry in the examination of trump attributions.

Previous systems are discussed, drawing from various historical sources, such as Arthur Waite, Aleister Crowley, A. E. Thierens, Eliphas Levi, and Antoine Court de Gebelin. The tradition of ascribing a Hebraic letter to each of the 22 trumps is also addressed, and a new system is proposed. This system interprets the threefold categorization of the Hebraic alphabet into the "3 mothers," "7 doubles," and "12 simples," according to the celestial mechanism of precession.