Rav Shmuel Birnbaum (1920 - January 6, 2008), was the Rosh Yeshiva of the Mir in Brooklyn. His diligence in Torah study was legendary and he was known to spend the entire day in the yeshiva's study hall discussing Torah topics with the students.
Rav Birnbaum was born in Poland and studied under the famed Rav Elchonon Wasserman. He later studied in the Mir Yeshiva located in the actual town of Mir, Poland. At the onset of World War II, he traveled with the rest of the Mir Yeshiva to Vilna, eventually ending up spending the war years in Shanghai, China. Following the war, Rav Birnbaum traveled with the remnants of the Mir Yeshiva to the United States and settled in Brooklyn, New York, where he married the eldest daughter of the Mir Rosh Yeshiva, Rav Avraham Kalmanowitz.