Alan Hirsch is a leading missional leader and thinker. I took Alan's D.Min. class on missional church at Fuller Theological Seminary, where we went through his book The Forgotten Ways. In this video, from the New Churches Conference, Alan explains how our culture have changed in North America, further enhancing the need to take a missional approach to church, rather than an attractional or extractional approach.
A great introduction to missional church.