Ferdinand Christian Baur’s treatise on the Gospel of Luke has been cited for a long time and has not been available in English as he wrote it. It occupies printed pages 391–531 of Kritische Untersuchungen über die kanonischen Evangelien, ihr Verhältniß zu einander, ihren Charakter und Ursprung (Tübingen: Ludw. Fr. Fues, 1847). The volume is ten preliminary pages and 626 pages of text. This book is the Luke treatise, with Baur’s preface. John, Mark, and Matthew remain in German.
I prepared the translation because the later English books on Marcion’s Gospel cannot be judged fairly while this argument remains available only in German. Adolf von Harnack’s 1921 reconstruction and his 1923 Neue Studien zu Marcion are in English, as is Theodor Zahn’s 1892 section “Marcions Neues Testament.” Baur’s treatise is the earlier case that the Gospel Marcion used is not a cut-down canonical Luke, but an earlier writing which the canonical Gospel later expanded.
What follows is Baur’s preface and then his argument, with his notes and the page numbers of the 1847 printing. Later reconstructions, modern critical texts, and the True Testament do not silently correct him. Greek and Latin remain as he printed them.