Yechiel Michel ha-Levi Epstein (Hebrew: יחיאל מיכל הלוי אפשטיין), (24 January 1829 – 25 March 1908), often called "the Aruch haShulchan" after his magnum opus, Aruch HaShulchan, was a Rabbi and posek (authority in Jewish law) in Lithuania.

Yechiel Michel Epstein was born on 24 January 1829 in Babruysk, Russian Empire (presently in Belarus) to Aharon Yitzchak and Rashka Epstein. His father was a builder and contractor who spend much of his time traveling for his work, often for the Czarist government.

He had one brother, Benjamin Beinush Epstein, who lived in Saint Petersburg. The two brothers stayed in touch over the years, and when Epstein needed to travel to Saint Petersburg—usually to submit his writings to the Russian censor before publishing—he would stay at his brother's house.

As a child, Epstein studied in a traditional Cheder. His original intent was to follow in his father's footsteps and work as a merchant, while dedicating time to daily Torah study. In his youth, he engaged in trade and was fluent in Russian, a skill not commonly found among rabbis at that time. However, Rabbi Eliyahu Goldberg, rabbi of the nearby town of Parichi (and a student of Rabbi Chaim of Volozhin), took an interest in young Epstein and convinced him to leave commerce and dedicate himself to Torah study. Soon after, Epstein left for the famed Volozhin yeshiva, where he studied for two years.

In Volozhin, he met and started a lifelong friendship with Rabbi Naftali Zvi Yehuda Berlin (the Netziv), who later became the rosh yeshiva (head) of the Volozhin Yeshiva. After finishing his studies there, Epstein married Berlin's sister Michlah. Berlin later remarried Epstein's daughter Batya Miriam after the death of his first wife.

After his marriage, Epstein returned to Babruysk and taught in the Altshul yeshiva there. He received semicha (rabbinic ordination) from Rabbi Eliyahu Goldberg, who had been appointed rabbi and Av Beit Din of the Mitnagged community of Babruysk in 1852.

By 1862, Epstein was serving as a dayan (religious judge) on Goldberg's beit din. Most of the family's income, however, came from his wife's fabric store. When eulogizing his wife, Epstein remarked—perhaps in exaggeration—that for 30 years Michlah ran the family store, and he did not even know where the store was located.

In 1864, at the age of 35, Epstein was appointed rabbi of Novozybkov (east of Gomel, now Bryansk region), a town with a large number of Hasidic Jews, mainly adherents of Chabad Lubavitch and Chernobyl. Several months after arriving in Novozybkov, Epstein traveled to Lubavitch where he visited Rabbi Menachem Mendel Schneersohn, also known as the Tzemach Tzedek, the third rebbe (spiritual leader) of the Chabad Lubavitch Hasidic Jews. His major endeavor during this period was writing his first work, Ohr LaYesharim, a commentary to Sefer HaYashar of Rabbeinu Tam. He printed the first volume of this work in 1869, but lacked the funds to publish more.