"Once, there was no 'secular'."
Even if not quite an Barthian bombshell, John Milbank's Theology and Social Theory: Beyond Secular Reason did really chock its audience (theologians and social theorists) when it first appeared nearly two decades ago. Even if the chock has worn off, the book in some ways rewrote the theological (and sociological) landscape. The book was the precursor of what later should be known as "Radical Orthodoxy".