Joseph Rosen

Joseph Rosen (, ''Yosef Rosin''; 1858 – 5 March 1936) known as the Rogatchover Gaon (Genius of Rogachev) and Tzofnath Paneach (Decipherer of Secrets—the title of his main work), was an Ashkenazi rabbi and one of the most prominent talmudic scholars of the early 20th-century. Rosen was known as a ''gaon'' (genius) because of his photographic memory and tendency to connect sources from the Talmud to seemingly unrelated situations. Rosen has been described as the foremost Talmudic genius of his time. He is also estimated to have written some 50,000 responsa, making him the most prolific responsa-writer in Jewish history. Provided by Wikipedia