Matthew Tuininga’s three-part series on the Two Kingdoms Doctrine (2K) published by Reformation21.org is an essential introduction to the contemporary debate within conservative Reformed circles concerning the role of the church in its relations to society and culture. Part One introduces the conflict, Part Two reviews John Calvin’s historical-exegetical approach to the temporal-spatial dimensions of 2K, and Part Three is an analysis of the scriptural basis of 2K. I recommend it for all who are making their first foray into the controversy. The Aquila Report has provided a very helpful analysis of some recent, especially vocal contenders with diverse perspectives on the issue. Finally (as far as introductions go), I recommend David VanDrunen’s Living in God’s Two Kingdoms—his book essentially reflects my position on this issue.