My review of Eliyahu Stern’s The Genius: Elijah of Vilna and the Making of Modern Judaism is up at The Forward:

Would you confuse Moses Mendelssohn and the Vilna Gaon, sometimes called the fathers, respectively, of Reform and Orthodox Judaism? Certainly not if you had seen their pictures. It’s hard to mistake Mendelssohn, with his clean-shaven cheeks and curly, uncovered hair, for the Gaon, usually depicted with flowing beard, enormous black kippah and prayer shawl. And it wasn’t just their getups. Mendelssohn, an 18th-century German Jewish philosopher who mingled with famous playwrights and bested Kant in an essay competition, is known for bucking rabbinic authority and beginning the Jewish Enlightenment. The Gaon, on the other hand, though Mendelssohn’s contemporary, spent most of his life secluded in study, writing recondite commentaries on the classics of rabbinic literature and ignoring the non-Jewish Lithuanians around him. The division between the two men — and by extension, between modernity and tradition — seems pretty clear.

Yet, in his new book, “The Genius: Elijah of Vilna and the Making of Modern Judaism,” Yale University religious studies professor Eliyahu Stern suggests that the Gaon was as fully modern as Mendelssohn.

To find out how, read on.