  Mendelssohn followed his rabbi from Dessau to Berlin at the age of fourteen. At twenty-one, he became a tutor in the home of a Jewish silk manufacturer, at twenty-five his accountant, subsequently his manager, and finally a partner in the business, in which he would work full-time for the rest of his life. But by twenty-five Mendelssohn had also mastered not only literary German but Greek, Latin, French, and English as well as a vast range of literature and philosophy in all those languages. He had also become friends with the critic and playwright Gotthold Ephraim Lessing and the writer and publisher Friedrich Nicolai, and begun an active publishing career. In 1755, before he turned twenty-six, Mendelssohn published Philosophical Dialogues on the model of Shaftesbury, the epistolary On Sentiments, and, with Lessing, Pope, a Metaphysician! The next year he published Thoughts on Probability and a translation of Rousseau’s second discourse On the Origins of Inequality. From 1756 to 1759 he collaborated with Lessing and Nicolai on the Library of Fine Sciences and Liberal Arts, for which he wrote two dozen reviews of new works in aesthetics and literature, and from 1759 to 1765 he contributed nearly one hundred reviews to Nicolai’s Letters concerning the newest Literature, discussing works not only in aesthetics and literature but also metaphysics, mathematics, natural science, and politics (Gesammelte Schriften, vol. 5.1 (1991), pp. 5–676). In 1761 he published the first edition of his Philosophical Writings, mostly on aesthetics, and in 1763 he took first place in a Prussian Academy of Sciences essay competition for an essay on Evidence in Metaphysical Sciences, beating out the entry by Kant. But as a Jew, he was denied entrance to the Academy by the “enlightened” Frederick the Great, even though he had the strong support of its members. In 1767, Mendelssohn published Phaedo: or on the Immortality of the Soul, loosely based on Plato’s dialogue of the same name, an immensely popular work. In the 1770s, after the onset of a “nervous debility” that he would henceforth claim prevented him from serious philosophical work, Mendelssohn began a translation of the Pentatuech and Psalms into modern German (but printed in Hebrew characters) that he hoped would preserve the Jewish religion while simultaneously facilitating the assimilation of Jews into German culture and society. His masterpiece Jerusalem, or on Religious Power and Judaism, in which he argued for the civil rights of the Jews by arguing that the state had no right to recognize any religion at all and therefore must allow all religions freedom from interference, was published in 1783. In 1785, he returned to philosophy one last time with Morning Lessons, a magisterial summary of his own version of Wolffianism. By this time, however, he was caught up in a strenuous controversy with the fideist philosopher Friedrich Heinrich Jacobi over whether his lifelong friend Lessing had been a Spinozist. In the midst of this controversy he died of in January, 1786, at the age of fifty-six.