For the past forty years the Knox-Robinson Ecclesiology has been the predominant ecclesiological model in the Sydney Diocese of the Anglican Church of Australia, one that emerged out of a series of theological contributions over two decades. The impact of this ecclesiology can be seen today across four continents (Australia, Europe, North America, Africa). Though pervasive in influence, there has--to date--been no extended systematic articulation of this ecclesiology, nor a serious and sustained appraisal of it. Here, the ecclesiologies of Donald W. B. Robinson (Vice Principal of Moore College 1959-1973, Archbishop of Sydney 1983-1992) and D. Broughton Knox (Principal of Moore College 1959-1985) are presented systematically, then analyzed and evaluated. Here, finally, is a thorough theological engagement with their provocative doctrine of the church.