This book explores the unique phenomenon of Christian interest in and engagement with Yiddish language and literature from the beginning of the sixteenth century to the late eighteenth century. It explains why some Christians were preoccupied with Yiddish and discusses the various ways in which they depicted this Jewish language and its literature in their writings. In the process, it sheds light on the broader linguistic, theological, cultural, and social concerns of early modern Christian authors and their intellectual environment. Discussing a practically unknown chapter in the history of Jews in the German lands, the book analyzes numerous Christian writings on Yiddish language and literature, many of which have not previously been subject to a systematic historical review. It thus provides an original contribution not only to the field of Christian-Jewish relations, but also to the broader fields of early modern German and German-Jewish history. Thanks to its interdisciplinary nature, the book will be of interest to anyone engaged in the fields of early modern European history, Jewish history, historical sociolinguistics, German studies, and Yiddish studies. Book jacket.