Simḥah Isaac ben Moses Luzki (Hebrew: שמחה יצחק בן משה לוצקי, Russian: Симха Исаак бен-Моисей Луцкий, Polish: Sima Izaak Łucki; 1716 – 1760/66), also known as the "Karaite Rashi" and "Olam Tsa'ir,"[1] was a Karaite Kabbalist, writer, and bibliographer.
Simḥah Isaac Luzki was born in the Volhynian city of Lutsk.
He resided in his hometown until the early 1750s, when he moved to Chufut-Kale, Crimea, where there was a flourishing Karaite community.
He was received into the house of the writer Mordecai ben Berakah Yerushalmi, and succeeded Samuel Kala'i as teacher of the city's bet ha-midrash.
His Light of the Righteous (1757) is a history of Karaite Judaism and its literature in which he presented a spiritual genealogy for the Sevel ha-Yerushah (the Karaite Jewish "unwritten" version of the Mishna)[2] from Judah ben Tabbai.