Rabbi Abraham Isaac Kook (1865–1935)

Rabbi Abraham Isaac Kook was the first Ashkenazi chief rabbi of the British Mandate for Palestine, the founder of the Religious Zionist Yeshiva Merkaz HaRav, Jewish thinker, Halachist, Kabbalist and a renowned Torah scholar. He was one of the most celebrated and influential Rabbis of the 20th century.

From wikipedia

See also the Jewish Virtual Library (includes photograph)