Between 1901 and 1914, Ernst Troeltsch wrote 150 reviews of new publications in theology, philosophy, the social sciences, and cultural history. Many of these critiques were published in obscure places, and their existence was hitherto unknown. Not only do they offer fasinating insights into Troeltsch’s train of thought, they also open up new perspectives on the debates that Heidelberg intellectual groups engaged in about the cultural meaning of religion and Christianity. Troeltsch reviewed texts by James, Simmel, and Rickert, wrote a major obituary note about his friend Georg Jellinek, avidly participated in the methodological debates of German historians, and developed in his reviews the integrative concept of theology as the cultural science of Christianity.