Joseph Ber Soloveitchik (b. 1904–d. 1993) was a major 20th-century American Orthodox rabbi, Talmudist, and modern Jewish philosopher. Scion of a distinguished Lithuanian rabbinical family, Soloveitchik was born in Belarus before relocating with his family to Warsaw. Under his father’s tutelage, the adolescent Soloveitchik devoted himself almost exclusively to traditional Talmudic study, mastering his grandfather Hayyim Soloveitchik’s “Brisker Derekh,” a modern methodology emphasizing scientific clarity and abstract jurisprudential conceptualism. He entered the Free Polish University in 1924, studying political science. In 1926, Soloveitchik commenced his studies at the University of Berlin, where he majored in philosophy and was attracted to Neo-Kantian thought, particularly philosophy of science. During this time, he also attended classes at the Orthodox Rabbiner-Seminar zu Berlin. In 1932, he received his doctorate under Heinrich Maier and Paul Natorp. His dissertation, “Das reine Denken und die Seinskonstituierung bei Hermann Cohen” (Berlin, 1933), dealt with the epistemological idealism of Hermann Cohen. He immigrated to the United States in 1932, and in 1941 he succeeded his father as the head of the Rabbi Isaac Elchanan Theological Seminary of Yeshiva University in New York. In this role, Soloveitchik trained several generations of Orthodox rabbis. From 1953, Soloveitchik also exerted a decisive influence on the Orthodox Jewish world in his capacity as chairman of the Halakhah Commission of the Rabbinical Council of America. His rulings included his unequivocal opposition to mixed seating in synagogues. He also served as honorary president of the Religious Zionists of America (Mizrachi). Soloveitchik was a remarkable orator in his native Yiddish and in English and Hebrew. The annual halakhic and aggadic discourse, which he delivered on the anniversary of his father’s death, attracted thousands of listeners and lasted from four to five consecutive hours. The tension between modernity and traditionalism manifested itself in every area of Soloveitchik’s public life. He staunchly defended the authority of the rabbinate, fought against unwarranted halakhic change, stood against the religious changes of the Reform and Conservative movements, and opposed theological dialogue with the Christian churches. Yet he pioneered Talmudic education for girls, broke with his family tradition in supporting Zionism, and advocated cooperation with the non-Orthodox—and even with Christians—in the pursuit of social justice and security for the Jewish people. His writings, marshalling a distinctively ambitious blend of Talmudic analysis with neo-Kantian, phenomenological, and existentialist motifs toward often-poetic explorations of themes in modern Jewish life and the modern religious predicament generally, have achieved currency well beyond the Orthodox Jewish world that constituted his primary audience.