The Screwtape Letters is a great read, and really, more palatable as Christian propoganda because it is straightforward in its goals.

Meanwhile, I actually think the gender roles in Narnia are much more open than in most fantasy literature. Namely - there are female characters at all! Who have speaking parts! And participate fully in the adventure! And risk their lives!

Yes, they are given different roles from teh boys, but much more than most of the other, even more contemporary fantasy literature I was reading as a kid.