I have recently published this article on the origins of Insider Movements in reference to an obscure document that I recently became aware of.
‘The 1938 Riggs Report on the “Near East Christian Council Inquiry on the Evangelization of Moslems”: an aborted beginning to the Insider Movement strategy’ in St Francis Magazine, Vol (2), April 2013.
Here is one section:
This is, in a nutshell, the Insider Movement strategy of mission to Muslims – not seeking to make Muslims into Christian, but Sunni [or Shi’a] Muslims into ‘followers-of-Jesus’ Muslims. Riggs explicitly points out that some other term than ‘Christian’ must be found and some other terminology must be developed’ (Part II, point 8). With updated spelling, some of the specific phrases used could be straight out of a contemporary journal article, as when he talks about, ‘believers who thus remain a part of their Moslem social-political group’ (Part II, point 11).