The Left Behind series is speculative theology as well, as there's a lot about it that goes against the current interpretation of Revelations. It's always seemed to me to be a form of intimidation rather than explication. Conversion through fear is hardly a profitable method for Christians to engage their non-Christian neighbors. Tolkien criticized Lewis's theology, but the Narnia books express the same Christian concepts of freewill and providence that are at the very heart of The Lord of the Rings -- Frodo chooses to be good and constantly relies on outside help to save him from his circumstances.
With regard to the claim that "No one comes to the Father but through me," we need to be careful that we don't take things entirely out of context. The New Testament book of Romans also says your nature is a law to yourself, written on your hearts and witnessed by your conscience, which suggests pure legalism is not the answer. Lewis's writings about Christianity rarely treated the subject of denominations, focusing instead on what he called "the rules common to the whole house." That was kind of Jesus's whole point.
Oh, and like everyone else said, this was a great article.
