The medieval Luther. Edited by Christine Helmer. (Spätmittelalter, Humanismus, Reformation, 117.) Pp. xii + 303. Tübingen: Mohr Siebeck, 2020. €99. 978 3 16 158980 5; 1865 2840 - Karant-Nunn, Susan C. (The journal of ecclesiastical history, 2022)