I am currently on the home-stretch of Paul Weston's Lesslie Newbigin Reader. I cannot recommend it highly enough.
The more I read, the less patience I have for any missional/emerging conversation that is not in knowledgeable and active conversation with Newbigin's writings. Newbigin consistently asks the difficult questions upon which the missional church rightly insists, but he steadfastly avoids Pelagian solutions that would turn missionary efforts into technical attempts to "get it right." Better said, Newbigin perceives the theological resources available to the whole system, rather than zero in on a particular perceived "issue", read in isolation of the whole. And "the whole" for Newbigin is always the Gospel of Jesus Christ.
A great example of this Christ-centered perspective at work comes in his consideration of denominational institutions. Rather than pit institutions in the bad camp and all other forms on the good, his analysis lands him at the heart of the challenge: a gospel-based rationale for freedom of thought that is capable of stepping outside of the inherited basis for that freedom in Western thought, which comes via the Enlightenment. So doing, he saves us the embarrassment that occurs when well-meaning Christians change everything only to realize that they have really changed nothing, because we have not been able to accurately see ourselves, much less sufficiently see ourselves.
Here are some highlights from his observations:
"...the denomination is simply the institutional form of privatized religion. It is a voluntary association of individuals. It is to put it simply - the outward and visible form of an inward and spiritual surrender to the ideology of our culture."
"They cannot confront our culture as Jesus confronted Pontius Pilate with the witness to the truth, since they do not claim to be more than associations of individuals who hold the same opinion."
"I believe that it is possible to act effectively in each local situation in such a way that the Christians together in each place begin even now to be recognizable as the Church for that place."
"If we are to escape from the ideology of the Enlightenment without falling into the errors of Corpus Christianum, we must recover a doctrine of freedom of thought and conscience that is founded not on the ideology of the Enlightenment but on the gospel."