Yitskhok Leybush Peretz, or I. L. Peretz (1835–1917), was a Yiddish and Hebrew writer, known for introducing modernist trends into Yiddish literature. Born in the town of Zamość Poland, he lived significant parts if his life in Warsaw, which he helped make a center of modern Jewish and Yiddish culture.

Peretz had been a Hebrew writer since the 1870s and was then known mostly as a Hebrew poet, although he was also capable of writing in Polish. He first expressed his ideas concerning Yiddish in his letters to Sholem Aleichem in the late 1880s; he “confessed” his affinity to Yiddish, referring to it as “the language of Beril and Shmeril,” in a Hebrew poem. His Yiddish writing debut was the long poem Monish (1888), which is considered to be the first folk narrative to be employed in modern Yiddish literature, with a style and plot heavily influenced by Goethe’s Faust.

His early Yiddish prose included a collection of stories titled Bekante bilder (1890). These texts embody psychological complexity, employing the form of internal monologues, and are considered to represent a significant development in modern Yiddish fiction. “The Messenger” (Der meshulakh) tells the story of the dying traditional Jewish-shtetl economy through the confessional story of an old man suffering from chest pains, reminiscing and hallucinating about his life, who is carrying a sum of money and a contract that he needs to deliver. “The Crazy Idler” (Der meshugener batln; in English often translated as “The Mad Talmudist”), consists of the internal monologue of a person suffering from a split personality disorder.