IN THE SUMMER of 1674, officials of the Dutch court carried out the recommendation of the States of Holland to ban the Theological-Political Treatise, a book that one of its more spiteful antagonists described in an anonymous pamphlet as “forged in hell by the apostate Jew working together with the devil.” It was an inauspicious debut for a work that Steven Nadler calls “one of the most important books of Western thought ever written.”

Poor Spinoza. So noble in intention, so reviled and misunderstood. Born into a Portuguese-Jewish family in Amsterdam during the flourishing years of the newly autonomous Dutch Republic, the brilliant young student “Bento” (or Baruch, as they called him at the synagogue) was only twenty-three years old when, on July 27, 1656, his own congregation on the city’s Houtgracht canal presented him with a formal ban of excommunication for his “abominable heresies” and “monstrous deeds.” The absurdity of this herem, the Hebrew term for the rabbinic ban, is that its recipient had not yet published any of the works that would eventually draw down upon his head violent accusations of atheism and immorality. The Ethics, the genuine masterpiece of speculative metaphysics that would earn him an eternal place in the canon of Western philosophy, did not appear until 1677, when its author was no longer alive. But well before this, rumor had already spread that young Bento doubted the law and denied the existence of God except in the “philosophical” sense, which is to say in the most minimal or heterodox sense that carried a whiff of heresy.

In early January of 1670, the mature philosopher published his most aggressive statement of political and religious criticism, under the compound Latin title Tractatus Theologico-Politicus. Anxious to avoid personal reprisals, he published it anonymously and with a cover page that misstated its place of publication as Hamburg. The measures were prudent, but ineffective. Within about three years its author was exposed and plans were afoot for seizing and suppressing all copies of his book. By the end of the 1670s the Catholic Church, eager not to be outdone, decided that the Treatise deserved a place on the Index of Prohibited Books, together with the Ethics and other opera posthuma, including his correspondence.

Steven Nadler has written a delightfully lucid and philosophically thorough account of the Treatise that helps to explain how and why this singular text became the object of such opprobrium and why we should see its appearance as “the birth of the secular age.” The general thesis is not entirely unique. The last two decades have seen an explosion of literature that celebrates Spinoza as the prophet of modernity. In 1992, Yirmiyahu Yovel authored a two-volume study on Spinoza and Other Heretics, entitled The Marrano of Reason and The Adventures of Immanence, respectively, that explored the question of whether Spinoza deserved the title of “the first secular Jew.” Yovel’s answer was no, but then yes: Spinoza could not have been the first secular Jew because “the concept did not yet exist,” but he was “a lost and suspended Jew, his existential case preceding his explicit ideas and prefiguring forms of Jewish existence in which he could not himself participate.”

Yovel then made this very indeterminacy serve as a paradigm for modern identity. The figure of the Marrano (who suffered persecution after the Spanish reconquista and was forced by circumstance into crypto-religious practice) became for Yovel the model for a species of modern selfhood that first emerged in the seventeenth century. And according to Yovel, Spinoza laid the foundations not only for the modern self, but also for the modern conception of the universe as well. The philosophical identification of God and nature—the thesis of pure immanence—laid down a pattern of naturalistic explanation that would inspire many of the greatest thinkers of modernity, from Goethe to Einstein. In Spinoza’s work, Yovel concluded, we are witnesses to an inaugural event of both history and philosophy that passed “from the world of revealed religion into a world of secular reason and immanence.” In a more recent work, called The Other Within, Yovel deepened and broadened this thesis beyond the case of Spinoza to argue that the Marranos heralded a species of split identity and secularism that now typifies much of modern experience.