Both real and fictional characters populate The Abyss, and the book has been compared to a tapestry because of its densely interwoven detail. The author uses historical document and anecdote to create a complex and tangled narrative of a particularly violent era; she relies less on physical description than on human voices to create a sense of time and place.

Amid this mass of cultural and historical information, however, Yourcenar’s focus is always Zeno. Such focus is not so simple and obvious as it might seem, because Zeno himself is a complex and tangled character whose intentions and actions often contradict one another. A fictional composite of Leonardo da Vinci, Erasmus, Paracelsus, and others, he is at the same time the Adam of the book’s epigraph, taken from Pico della Mirandola. The epigraph is one of the thematic keys to the novel.

I have given you, O Adam, no fixed abode, and novisage of your own, nor any special gift, in order thatwhatever place or aspect or talents you yourself will havedesired, you may have and possess them wholly in accordwith your desire and your own decision. . . .

Yet Zeno is by no means so free as this passage suggests, and one of the book’s overarching metaphors is prison. As an arrogant twenty-year-old, he half-jokingly remarks to Henry Maximilian that no one would be so besotted as to not want to take a look around this earthly prison, and he spends the rest of his life doing precisely that, as the figurative prison of the world becomes the close confinement of part 2 and the literal prison of part 3. He investigates both the tangible and the intangible, from the eye of a frog to human passions to the very existence of God. Zeno, more often than not in the sevice of a king or emperor, is the most dangerous of subversives, because everything—animal, vegetable, mineral, spiritual—is subject to dissection and scrutiny.

Another consistent metaphor is fire, Zeno’s native element. Newborn Zeno is kept warm not by his indifferent mother, but by the fire’s embers; as a youth he ignores Henry Justus’ royal guests to brood by the fireplace; later he makes Greek fire for the sultan and a brazier for the ailing prior. As astronomer, he studies the distant fire of the stars, and as alchemist, he is that element’s constant companion. His last moment is presided over by a scarlet globe, “a blinding daylight which was, at the same time, night.”

The original French title of The Abyss was L’uvre au noir, “the work in black,” a term taken from alchemy. The grand experiment of creating the philosopher’s stone that would transmute base metals to gold required three stages: nigredo or black, for the disintegration of the original materials; albedo or white, for the dawn or rebirth of a new substance; and finally rubedo or red, for the fully matured and ready substance. As Europe burns and disintegrates, so does Zeno. He reaches his darkest point in the chapter called “The Abyss” when, virtually immured in the hospice in Bruges and weary of rational observation, Zeno turns inward, losing his sense of time, place, and substance: He is absorbed into his own bones, into the walls of his cell, into the water with which he washes, into his own memories. As he emerges from this dissolution of the self, he finds new energy and focus in his healing, reaching a state of sustained concentration that his friend the prior might have called mental prayer. He also feels true compassion for the first time. As Zeno dies, his vision turns as red as the blood escaping his body, and he is ready for a new stage unknown to either him or the reader.