Martin Luther's Small Catechism as a foundation of a modern dogmatics: it is the objective of this book to state as clear and simple as possible what Christian faith is according to a Protestant understanding. An authentic Protestant Christianity implies individually made interpretations of life. For this a guideline is needed which enables to locate the biblical origins and contours of Christianity in the basic determinations of life. Martin Luther's Small Catechism has been able to do this exemplarily at the time of the Reformation. Therefore, a modern interpretation of Protestant Christianity can draw on Luther's text and analyse it with the help of current concepts.