@ Bob
I found it interesting that you labeled the Left Behind series as 'genre' fiction. Within the Christian community those books are largely regarded as 'speculative guesswork' i don't know anyone that would call them sci-fi, or fantasy, because of how closely the authors tried to stay to the events foretold (in very involved symbolism) in the book of Revelation.
There ARE actual others that delve into sci-fi and fantasy territory that also publish themselves as "Christian Authors." (I personally hate the term, as I hate "Christian Music" and Christian Films". These are people that are simply catering to a specific audience for backing, while turning their back to the people that, if we are to follow the Bible, need to hear the Christian message more.)
A couple of these authors that write fantasy and science fiction with Christian labeling are; Ted DekKer, author of the Colors trilogy (Black, Red, and White) and Three, (which was made into a half decent movie.) as well as waaay too many others. Another author worth mentioning is Robert Liparulo, author of a book called "Comes A Horseman" that delves into a character that believes he is the antichrist, and even gets to the point of infiltrating the Vatican, with a host of followers. A REALLY tough sell in the so called 'Christian' market.
"Comes a Horseman" is a really good read, and I highly recommend it. Ted DekKar's work though can be a bit preachy and heavy handed with it's allegory and is a perfect example of a lot of the problems of authors writing to a solely Christian audience.
As for your essay on C.S. Lewis, thank you, I haven't heard much about his upbringing and the psychological analysis is enlightening.
If you are interesting in understanding the 'logic' that Lewis saw from his collegues in Oxford, seriously check out an essay he did called "Mere Christianity". You've probably heard of it, but if you haven't read it, it's got some great stuff in there, especially the first couple chapters.