ZALCSTEIN, GECL (1773–1841), dealer in books and ancient Polish manuscripts. A follower of the ḥasidic leader *Jacob Isaac ha-Ḥozeh of Lublin, Zalcstein opened a book and antique shop in Warsaw around 1800. On his many visits to the Polish aristocracy he obtained ancient manuscripts and books, thus acquiring an extensive knowledge of Polish works. He aided the historian J. *Lelewel and the bibliographer K. Świdziński in their research, and through his devoted assistance the libraries of the University of Warsaw and other academic institutions were enlarged. His shop became a meeting place for Polish intellectuals. In 1831 Zalcstein founded a mirror factory and transferred the management of his bookshop to his son, leib, a Kotsk ḥasid. After a few years of meager success Zalcstein closed the factory and returned to managing his bookshop. In the 1830s, because of his connections with Polish intellectuals, he was suspected of subversive activities by the Russian authorities. His wife took over the shop after his death, and his son Leib engaged independently in book-selling and publishing from 1820 until his death in 1860. His annual Kalendarz Astronomiczny i Gospodarski ("Astronomic and Economic Calendar") appeared for 40 years and was a pioneering work of agronomical information in Poland. Zalcstein's younger son, jonah baer, also opened a bookshop, and descendants of the Zalcsteins were prominent booksellers, publishers, and antique dealers in Warsaw in the 1920s.
J. Shatzky, Geshikhte fun Yidn in Varshe, 2 (1947–49), indexes; K.W. Wójcicki, Pamiętniki dziecka Warszawy (1909), 58–59; S. Kastik, Zdziejów Oswiecenia ẓydowskiego (1961), 192–97.