Menashe Klein
Menashe Klein (1924–2011) (Hebrew: ר' מנשה קליין), also known as the Ungvarer Rav (Yiddish: אונגווארער רב), was a Hasidic Rebbe and posek (arbiter of Jewish law). He authored 18 volumes of responsa, spanning over 50 years, entitled Mishneh Halachos. Additionally, he authored some 25 other seforim, including a commentary on Simeon Kayyara's BeHag. Toward the end of his life, he relocated from Brooklyn, New York to Jerusalem.