I just started reading a fascinating new book called Planet Narnia. The author, Michael Ward, argues that the main organizing principle behind C.S. Lewis' Chronicles of Narnia is in fact the seven medieval planets--the 'seven heavens' of medieval cosmology.
And it seems that Dr Michael Ward has a web site here.
There are more blog comments on the book here: Between Two Worlds: Planet Narnia?
and here C. S. Lewis Blog: Narnia and the Seven Heavens
C.S. Lewis secretly based the Chronicles of Narnia on the seven heavens. The imagery associated with each planet provided him with his symbolic raw materials. The planetary symbols govern the shape of each story, countless points of ornamental detail and, most importantly, the portrayal of the central character, Aslan.I wonder how that ties up with Lewis's descriptions of the planets in That hideous strength.
Here is a brief summary of how the Chronicles relate to the planets
The Lion, the Witch and the Wardrobe – Jupiter
Jupiter was the best planet and Lewis’s favourite. Jupiter was the planet of kingship, and this story is a clash between the children’s destiny as kings and queens of Narnia, under the ‘King of the Wood’, Aslan, and Edmund’s mistaken attempt to become king under the evil White Witch. Jupiter brought about 'winter passed and guilt forgiven', according to Lewis’s poem, ‘The Planets’, and in this first Narnia Chronicle the White Witch’s winter passes and Edmund’s guilt is forgiven.