Reuben Zak
Reuben ben Tsvi David Zak lived in Ustile in the Volhynia region (today Ustylúh, Ukraine). He was a dedicated follower of Hasidic tsadik David Moshe Friedman of Chortkov (1827–1903), the fifth son of the Ruzhiner rebbe and a significant Hasidic leader in his own regard. Zak was a prominent chronicler of teachings and tales of R. Israel Friedman of Ruzhin (1796–1850), the first Ruzhiner rebbe and founder of their Hasidic dynasty. Zak’s first book was Keneset Yisra’el, published in 1903, followed by the anthologies Beit Yisra’el (1913) and Kerem Yisra’el (1930). Since Israel of Ruzhin wrote no books himself, works like Zak’s serve as valuable testaments to oral traditions within that community with regard to its leader and his teachings.