Into Narnia? Want to go deeper? This is excellent book to aid with that. Not written for professional philosopher. Not written for those who just want to leave Narnia as the entertaining read it is, even for child in all of us.
This delves into the philosophy behind Narnia which for sure Jack was into as well, for he taught philosophy early on in his career and was avid philosopher all his life.
Here parallels to such metaphysics as time, epistemology, altruism, objective morality, and more, they are each treated here from Narnia position by this group of committed philosophers. There is definite Christian bent to their worldview, as there was with Jack's. The article on Aslan and Other Religions explores the stickiest issue with Lewis' theology, that of inclusivism. This discussion brings forth the issues in contention. Likely this is why many Christian apologists shy away from Lewis, due to his likely unbilbical stance here. Sure we would all like to believe this somewhat, but the Scripture evidence is lacking.
I particularly found Kevin Kinghorn's work on virtue epistemology fascinating, especially as he sees it in relation to Uncle Andrew's inability to hear the Talking Animals.
Further, Michael and Adam Peterson's venture into time and eternity from Narnian view is cogent and timely, ha! Angus Menuge tackles the gripping topic of "why Eustace Clarence Scrubb"almost deserved his name. This is engagement with modern secularism exposing its bias which even it itself cannot provide all evidence it seems to demand from other views. Closeness to Transcendent is vital area to explore and this will help.
Hopefully for those kin to engage in these thoughts, this is good source to take off exploring these some twenty authors ventures into Aslan's country.