C.S. Lewis writes the following in his essay, "Sometimes Fairy Stories May Say Best What's To Be Said":
"Some people seem to think that I began by asking myself how I could say something about Christianity to children; then fixed on the fairy tale as an instrument, then collected information about child psychology and decided what age group I’d write for; then drew up a list of basic Christian truths and hammered out ‘allegories’ to embody them. This is all pure moonshine. I couldn’t write in that way. It all began with images; a faun carrying an umbrella, a queen on a sledge, a magnificent lion."
It strikes me that some people's assumptions about Lewis's writing of Narnia are somewhat similar to the modern evangelical strategy of ministry.