Hungarian rabbi; born July 7, 1842, at Miskolcz; studied philosophy at the University of Prague, attending at the same time lectures on Jewish theology by Chief Rabbi Solomon Rapoport. In 1863 he received his Ph.D. degree and his rabbinical diploma, and was appointed director of the Jewish communal school in his native city, where he officiated also as preacher at the Great Synagogue. In 1869 he was called as rabbi to the Reform congregation ("Congress-Gemeinde")of Ungvar; in 1876 he went to Papa; and in 1880 he accepted a call as chief rabbi to Nagy-Becskerek, which office he still (1904) holds. He is a member of the board of examiners of the Rabbinical Seminary at Budapest.
Klein's works include Hungarian translations of (1) Maimonides' "Moreh Nebukim," under the title "A Tévelygök Utmutatója," in three volumes, with notes (1878-91), and (2) Jedaiah Penini's "Beḥinat 'Olam," under the title "A Lélek Tragediája" (1901).
- Kiszlingstein, Könyvészet;
- Szinnyei, Magyar Irók Elete, vi. 513.