(quote) David-978346 said: Interesting question, and there's a lot to be said about it.
I think fiction, and in particular genre fiction, can be a powerful weapon in evangelization. A good chunk of what makes a culture is the stories it tells, and we take a surprising number of the ideas and assumptions which we live by from the stories we hear.
In terms of what you're specifically talking about, regarding mythology, I think the main use of mythology is in giving abstract ideas substance and making them concrete. Taking a random idea from Tolkien as an example, the derivitiveness of evil - that evil has no existence of its own but is only corrupted good - is a fairly abstract idea which Tolkien makes explicit by the existence of the Orcs, the Nazgul, and so on as corrupted beings.
So, myth and fiction can be great tools for evangelizing, but I'd add a word of caution: don't focus too much on evangelizing. No one will read your books just because they express a Catholic worldview (or at least, very few people). Anyone would read your book, regardless of the view it expressed, if it's a good story. I think the biggest problem with Catholic art in the modern world is that it focuses too much on being Catholic and not enough on being good.
Okay, hope that's enough to get started with.
Great comments about mythology and story telling. I especially agree with the closing remarks. Good stories are read because they are good, not because they are Catholic. The best stories contain the Truth, therefore they are already evangelistic in nature.