KOTLER, AHARON (1892–1962), was a rabbi and prominent educator in eastern Europe and the United States. A child prodigy, Kotler was sent as a youth to study in the famous musar-yeshivah of Slobodka (near modern-day Kaunas, Lithuania), which emphasized Talmudic studies as well as ethics and self-improvement. After his marriage to the daughter of Isser Zalman Meltzer, the head of the yeshivah in Slutsk, White Russia, Kotler moved to Slutsk and began to teach in the yeshivah. In the wake of World War I he moved the yeshivah from the Soviet-controlled area to Kletzk in Poland. There he became one of the best-known figures in Polish rabbinical circles. He was the youngest member of the Council of Scholars and Sages of Agudat Yisraʾel.

In 1935 Kotler visited the United States, where he discussed the need for an American yeshivah that would be designed not for the training...