Avraham Yishayahu Karelitz (Abraham Isaiah Karelitz) (1878-1953) known by his pen name as the Chazon Ish (in Hebrew: "Vision [of] Man"), was a Lithuanian born Orthodox Judaism rabbi who became leader of Haredi Judaism in Israel. His final 20 years were in Israel from 1933 to 1953.

Born in Kossow, Avraham Yeshayahu received his education from his father, head of the beth din (religious court) at Kossow. In 1911 he published his first work on Orah Hayyim and other parts of the Shulhan Arukh (Code of Jewish Law by Rabbi Yosef Karo) in Vilna, anonymously under the title Chazon Ish, the name by which he became almost exclusively known.

He moved to Vilna in about 1920, and became close to Rabbi Chaim Ozer Grodzinski consulted with him in all religious and communal matters. Encouraged by Rabbi Grodzinski and with Rabbi Abraham Isaac Kook’s help, the Chazon Ish settled in the British Mandate of Palestine in 1933.

Karelitz manifested unusual talent and diligence from an early age. He devoted his life to the study of the Torah and Talmud, although also learning such sciences as astronomy, anatomy, mathematics, and botany, since he felt that knowledge of these subjects was necessary for a full understanding of various aspects of Jewish law and practice. After his marriage, he continued to lead an extremely modest life, his wife providing for their needs while he spent day and night in deep Talmudic study. He did not have any children

The reputation of the Chazon Ish for saintliness and knowledge was widespread and people from all walks of life would frequent his home, for scholarly discussions or to seek advice on religious, business, or personal problems, or simply to receive his blessing. When in 1933 he settled in the Land of Israel, his house in Bnei Brak became the address for thousands who sought his guidance.

Holding no official position, the Chazon Ish nevertheless became a recognized worldwide authority on all matters relating to Jewish law and life. He was not appointed as communal leader, yet he exerted an enormous influence on the life and institutions of religious Jewry. He did not publish many responsa, but became the supreme authority on halakhah (Jewish Law). David Ben-Gurion, the prime minister of Israel, visited him once to discuss political-religious issues.

A lover of Zion, he belonged to no official movement. He loved and respected all beings and as equally admired by all, without exception – by Hasidim, Mitnagdim, Ashkenazim, Sefardim, Haredim, Datiim, Hilonim, Zionists, and others. Today there is hardly a town in Israel without a street named in his honor. Although essentially an academic scholar, he applied himself to practical problems, devoting much effort to the strengthening of religious life and institutions. His rulings on the use of the milking machine on Shabbat and on cultivation by hydroponics during the sabbatical year are two illustrations of his practical approach. A model of modesty and kindness, the Chazon Ish wrote over 40 books in clear Hebrew, in polished and precise style, which are models of lucidity and brilliance.

The true legacy of the Chazon Ish is the promotion of clarity in Talmud study, devotion in the worship of God, and loving-kindness in human interactions.