Intro To Transcendental Critique
Roy Clouser's The Myth of Religious Neutrality has recently appeared in a new revised edition by Notre Dame Press. This work is the best introduction to the foundation of Dooyeweerdianism available in the English language. I can't recommend it highly enough. See a comment on the first edition here.
Also, check out the Roy Clouser Pages. I particularly recommmend his article "Is God Eternal?".