Lesslie Newbigin (1909-1998) is my nemesis. Okay, maybe not exactly that - but he is my opposite. I'm a Subcontinental who moved to a Western nation and moved from Anglicanism to Presbyterianism; he was an English Presbyterian who went to South India as a missionary and eventually became an Anglican Bishop.
Newbigin was heavily involved in ecumenical movements. He was instrumental in creating the Church of South India - the Indian equivalent of Australia's Uniting Church. He was also significant in the World Council of Churches. His work on a missionary encounter between the Gospel and Western culture helped spawn the missional church movement.
From my perspective, Newbigin isn't strong enough of the Bible itself as revelation, and (consequently...?) too optimistic of the Church as bearing God's revelation. But, his analysis of Western culture is, I think, spot on. I'm gonna post some quotes over the next few days.