A. von Harnack's Marcion: Das Evangelium vom fremden Gott, Leipzig, 1924 remains the classic study on Marcion. In English, E. C. Blackman, Marcion and his Influence, London, 1948 and J. Knox, Marcion and the New Testament, Chicago, 1942. The dictionary articles by G. Krüger, Prot. Real. Encyc (3rd ed.), xii. 1903, 266-277, E. Amann, Dict. Theol. cath. , ix.2 ( 1927), 2009-2332 and G. Salmon, Dict. Christ. Biog.iii (1892), 816-824 should be consulted, and so also, H. Lietzmann's chapter, 'Marcion ' in Geschichte der alten Kirche (Berlin, 1937) i, 265-282, and Rendel Harris, ' Marcion's Book of Contradictions', John Rylands Library Bulletin , Vol. 8, 1924.
