A noted Bach scholar, Rathey (Yale) presents a masterful holistic study that includes both in-depth musical analyses and in-depth investigations of the environment in which the oratorio was created. Rathey carefully explains Bachs considerable use of the parody technique, in which he reworked music he had written for earlier cantatas. Offering a detailed study of many contemporaneous writings about the role of Christmas in the Lutheran theology and culture of Bachs world, the book provides crucial understanding of Bachs musical and spiritual interpretations of the text. This important study is a must for students of music and will also be helpful for the study of German theological and cultural history.