Classic Marsden. He did his homework and dug up some interesting anecdotes, offering a strong narrative, a clear outline and analysis, and some insightful points along the way. He did some “reception history” by looking at ways that people have reacted to Lewis’ book, including his famous “trilemma” (Jesus is liar, lunatic, or Lord).
One insight from the book that struck me: Lewis didn’t use reason to prove Christianity so much as to clear away objections and then invite others to see and experience what he did in the faith.
Another point that helped me was that though Lewis has been instrumental in the Tiber-crossings of some prominent ex-Protestants, some of those very people (including a graduate of my [very Protestant] alma mater, Dwight Longenecker) have pointed out that Lewis’ famous hallway metaphor in the preface to Mere Christianity is actually itself a Protestant conception of ecclesiology:
Ian Kerr, who acknowledges that Mere Christianity was an “enormous influence” on him in his teens, argues…: “The Roman Catholic Church would have to insist that the envisaged house is the Roman Catholic Church, with the other communions as more or less attached to it as annexes our outbuildings.” So, Kerr concludes, “The whole concept of a common hall with different rooms opening off it is not an acceptable ecclesiastical model from the Catholic point of view.” (130)