Joseph Perl (1773–1839), a famous author and teacher, was a leading member of the Haskalah and a decided opponent of Hasidism.
Portrait of Joseph Perl (Translation of the caption: "Portrait of Joseph Perl. The original is in the Tarnopol Perl School [based on an engraving published in Lemberg]"), nineteenth century, unknown artist; source: יוסף פערלס יידישע כתבים, Vilnius 1937, Wikimedia Commons, http://en.wikipedia.org/wiki/File:Joseph_Perl.jpg, public domain.