In the forward to his Evangelical Theology, Karl Barth recaps his tour of the United States earlier that year.
As I approach Stringfellow's work, I like to remember the famous admonition Barth gave to his American readers:
What we need on this and the other side of the Atlantic is not Thomism, Lutheranism, Calvinism, orthodoxy, religionism, existentialism, nor is it a return to Harnack and Troeltsch (and least of all is it "Barthianism"!). but what I somewhat cryptically called in my little final speech at Chicago a "theology of freedom" that looks ahead and strives forward (p. xii).
I don't mean to suggest that Stringfellow is the "child of promise"; in fact, I don't believe there ever has been or ever will be such a person, neither in the United States, Germany, Switzerland, Rome nor anywhere else. I mean rather to propose that the young theologian and troublemaker may have caught more than a whiff of that spirit of freedom to which Barth was pointing -- the freedom that the children of God have in Christ Jesus.
Barth, Karl, Evangelical Theology: An Introduction (New York: Holt, Rinehart & Winston, 1962).
Dancer, Anthony, An Alien in a Strange Land: Theology in the Life of William Stringfellow (Eugene, OR: Wiph & Stock, 2011).