Y. L. Peretz (1852-1915) produced not only an extraordinary body of literary work, he presided over the shaping of a new diaspora culture. Peretz published numerous essays and polemics on the new culture in the emerging Warsaw Yiddish press. These writings have received little attention; indeed, their texts and dating are unreliable in the existing Peretz anthologies. For several years I’ve been collecting these essays directly from the Yiddish press. I presented the first results of this research, a study of Peretz during the 1905 Revolution, as the Clara Sumpf Lecture in Yiddish Studies at Stanford University in 2007. My current research focuses on a series of articles that Peretz published between March 1 and May 11, 1911 in the Warsaw daily Der fraynd entitled “Paths That Divert from Yiddishkayt.” Peretz here presents, during a period of political reaction and increasing national antagonisms, his developing vision of the past and future of the Jewish people. The articles are laced with scathing attacks on most of the cultural and political options confronting Jews of the time. His chief antagonist was Hillel Zeitlin (1872-1942), a religious philosopher and journalist and a major figure in Warsaw literary life. Zeitlin published a series of articles entitled “Letters to Jewish Youth,” in which he advocated a return to religious orthodoxy linked to a Jewish national perspective. In one of these articles, Zeitlin says of Peretz that he had a heaven but that there was no God in his heaven. Peretz responds by calling Zeitlin the Prophet of Yesterday, and refers to his teachings as Khumesh with Rashi, i.e., the curriculum of the unreformed Jewish elementary school. At stake is a conception of a new Jewish culture (“secular”? “religious”?) that resonates remarkably well today.