On July 27, 1656, the Jewish community of Amsterdam expelled Baruch de Espinoza. As Josef Kaplan's work has shown, the community used ḥerem as a standard disciplinary instrument, usually on a temporary basis. In Spinoza's case, however, the Amsterdammers issued a fierce and permanent denunciation on grounds of “abominable heresies” and “monstrous deeds.” Speaking for the community, the rabbis “excommunicate, expel, curse and damn” him with formidable intensity. In addition to forbidding contact with Spinoza himself, the ḥerem concludes with a prohibition against reading “any treatise composed or written by him.” What were these heresies and deeds, and why was the ḥerem so harsh? Only twenty-three years of age, Spinoza had not yet, so far as we know, begun to write the philosophical works—the Tractatus Theologico-Politicus (1670) and the Ethica (1677), the former published anonymously, the latter only posthumously—that would to make him notorious well beyond the domain of the Portuguese Jews. Looking at the later texts, it is not difficult to imagine the cause of the outrage: Spinoza denies creation and divine providence, individual or personal immortality (together with the doctrine of eternal reward and punishment), and the truth of the Torah. But what exactly was Spinoza doing in the mid-1650s, and why were his ideas and actions so offensive to the community?