Obviously the authors of 1940 were no less inclined to hyperbole than we might be today, but just to let the force of this roll around in your brain a bit longer, here's a blurb from the forward to the book, written by Reinhold Niebuhr:
"Whatever may happen ultimately to the movement associated with Barth's name, one contribution is securely established. The bondage of Protestantism to the religious principles of the Enlightenment has been broken by the force of a new theological method. Whether the twentieth-century heirs of the Reformation can, or will, recover thereby the peculiar genius of their legacy is a secondary question" (107).
It is worth noting when this book was written, because this was before Barth left us the most mature expression of his theological services; the bulk of the Church Dogmatics, including his Doctrine of Reconciliation.
"Professor Lehmann’s very vigorous treatise on the Reformation doctrine of forgiveness, as revived by Karl Barth in reaction to the dissipation of the doctrine in liberal theology, brings the central issue of Christian theology into sharp focus. That this is the central issue of Christain theology, is a fact not yet fully recognized in the modern church. Sooner or later it must be recognized" (x).
It is hard to be an evangelical these days and go very long without hearing gestures toward (or even promises of) another reformation in the Protestant Church. I think there is a grain of truth to the perception that such a thing is either impending or direly needed -- but, having read a lot from cultural analysts, the New Reformed and the Emergents on this score, the more I read Barth the more I am convinced that Paul Lehmann was right. To me it is both disheartening and promising that we are into the twenty-first century now and this has yet to really catch on.