Tuomo Mannermaa (b. 29 September 1937 Oulu, Finland) is professor emeritus of ecumenical theology at University of Helsinki. He is known especially for his theological criticism of the Leuenberg Concord and his research on the relationship between justification and theosis in the theology of Martin Luther. His initiating and furthering this research caused him to be regarded as the father of "The New Finnish Interpretation of Luther" or "the Finnish School of Tuomo Mannermaa".
Finnish School 
Mannermaa led the development of "The New Finnish Interpretation of Luther" that presents Luther's views on salvation in terms much closer to the Eastern Orthodox doctrine of theosis rather than established interpretations of German Luther scholarship. This research has recently been presented in English in an anthology of papers edited by Carl E. Braaten and Robert W. Jenson in a work entitled, Union with Christ: The New Finnish Interpretation of Luther. Mannermaa states, "the external impulse for this new wave of Luther studies in Helsinki came surprisingly from outside the boundaries of Luther research. It came from the ecumenical dialogue between the Evangelical Lutheran Church of Finland and the Russian Orthodox Church that was initiated by Archbishop Martti Simojoki at the beginning of the nineteen-seventies."
The New Finnish Interpretation has been challenged because it downplays Luther's roots in key theological developments in Western Christendom, and it characterizes Luther's teaching on Justification as based on Jesus's righteousness which indwells the believer rather than Jesus's righteousness as imputed to the believer.
Selected works 
- Von Preussen nach Leuenberg: Hintergrund und Entwicklung der theologischen Methode der Leuenberger Konkordie. Lutherisches Verlagshaus, 1981 ISBN 3-7859-0480-0
- Christ Present in Faith: Luther's View of Justification. Fortress Press, 2005 ISBN 0-8006-3711-9
- Rethinking Justification. A Review of Christ Present in Faith: Luther's View of Justification by Tuomo Mannermaa Developing Theology * Mannermaa, Tuomo. "The Doctrine of Justification and Christology Chapter A, Section One of The Christ Present in Faith". Concordia Theological Quarterly 64 (2000)
- Dorman, Ted. Review of "Union With Christ: The New Finnish Interpretation of Luther". First Things, 1999.
- Tuomo Mannermaa, "Why Is Luther So Fascinating? Modern Finnish Luther Research," Union with Christ, (Grand Rapids: Eerdmans, 1998), 1.
- William Wallace Schumacher, "'Who Do I Say That You Are?' Anthropology and the Theology of Theosis in the Finnish School of Tuomo Mannermaa" (Ph.D. diss., Concordia Seminary, St. Louis, Missouri, 2003), 260 et passim. Cf. also the papers that constitute Union with Christ: The New Finnish Interpretation of Luther by various authors; cf. also Robert Kolb and Charles P. Arand, The Genius of Luther's Theology: A Wittenberg Way of Thinking for the Contemporary Church, (Grand Rapids, Michigan: Baker Academic, 2008), 48: "These views ignore the radically different metaphysical base of Luther's understanding and that of the Eastern church, and they ignore Luther's understanding of the dynamic, re-creative nature of God's Word."