The Abyss is the story of one man’s devotion to truth. As Zeno relentlessly searches for knowledge, vast historical forces—Catholicism and Protestantism, France and the Holy Roman Empire, agrarianism and commercialism—turn Reformation Europe into a bloodbath. Marguerite Yourcenar’s careful documentation adds to this continent-sized clash between dissidence and dogma a great sense of period realism.

The story opens in 1530. Henry Maximilian Ligre runs into Zeno outside Dranoutre, Henry Justus Ligre’s Belgian country estate, and the two discuss plans. At sixteen, Henry Maximilian is planning to serve with King Francis I. At twenty, Zeno is leaving to study alchemy in Spain. Both have abandoned the merchant House of Ligre. Henry Maximilian has chosen war, poetry, and women. Zeno has chosen a rendezvous with himself.

A flashback recalls Zeno’s youth. His father, Alberico, was a friend of Michelangelo and prelate to Cesare Borgia. While staying with Henry Justus,his business agent in Bruges, he is smitten with Hilzonda. He later abandons her when she becomes pregnant with Zeno.

Alberico, a Roman cardinal by age thirty, is killed in an orgy. Simon Adriansen then courts Hilzonda. Zeno learns the classics from Canon Campanus and medicine from Jan Myers, and designs the mechanical looms used in the Ligre workshops. At the School of Theology in Louvain, Zeno comes to disdain dogma. His summer vacations are spent at Dranoutre, where his best moments are passed in alchemical speculations on the changing color of the leaves and the combustion of charcoal. He pities the numerous religious sects he sees forming and wishes to renounce his clerical vows.

One evening at Dranoutre, Henry Justus mounts a royal reception for Marguerite of Austria, who is there to ask for a loan. Henry Justus’ weavers interrupt the festivities to request a raise and a pardon for their foreman, who has destroyed the looms. Henry Justus grants the loan, but no raise or pardon. Zeno, equally disgusted by the cynicism of the high life and the technophobia of the low life, departs in search of another critical mind. He will remain underground for the next twenty years.

Simon and Hilzonda are married and move to Munster, where they help found an Anabaptist City of God. A joint Catholic and Protestant army lays the city to siege. Inside, a mountebank proclaims himself God, executes the underzealous, and takes seventeen wives. The troops overrun the city and resume executions. Simon returns from a fund-raising expedition to find his wife beheaded. On his deathbed, he writes Salome, his sister. She will rear Simon’s surviving daughter, Martha.

Salome is married to Martin Fugger of Cologne, whose money makes him more powerful than any prince of Europe. The elder Ligre has sent his son, Philibert, to learn banking under Martin. Martin betroths Philibert to his blood daughter, Benedicta. Benedicta, however, is stricken by the plague. Zeno, traveling incognito, visits and treats her. She dies, but Martin merely substitutes Martha’s name on the wedding contract.

During the Council of Trent (1551-1552), Henry Maximilian again encounters Zeno at an inn in Innsbruck. Maximilian is employed by Marshall Piero Strozzi to spy on the Pope’s messenger, Nuncio della Casa. Coincidentally, Zeno is Nuncio’s physician and alchemist. The two cousins compare life histories. Zeno has performed dissections in Montpellier, invented liquid fire in Algeria, published a philosophical treatise, had an Arab male servant as his lover, and fought the plague of 1549. Henry Maximilian has served both France and Spain as a mercenary for twenty-five years. He sees Europe not only as a puppet show, with financiers pulling the strings, but also as a beauty pageant, with many a...