The article investigates how early modern Christian authors perceived the names of Jews and their naming customs. Based on a variety of printed sources, like ethnographic reports, language manuals, criminal investigations, and academic texts, the article does not only depict early modern Jewish names and rituals but sheds light on the Christian authors, their sources, and their changing perceptions. While theologists and converts in the 16th and 17th century focused primarily on naming customs, authors after 1700 became increasingly interested in contemporary names - their creation, their meanings, and their variations. Closely connected to the negative perception of the Yiddish language, Jewish names were seen as a source of potential fraud and the acquisition of knowledge on the matter as a necessary means of control.