Ward proposes that Lewis used medieval cosmology—the "Seven Heavens"—as a secret imaginative key to give each book its unique atmosphere and "Kappa Element" (the quality of a story that remains in the mind after the plot is finished). According to this theory, each book corresponds to a specific planetary influence:
: Mercury (Language, speed, and thieving). The Narnia Code: C. S. Lewis and the Secret of ...
: Jupiter (Kingship, bringing an end to winter, festive abundance). : Sol (The Sun) (Light, the slaying of
: Sol (The Sun) (Light, the slaying of dragons/lizards, and alchemical gold). Significance and Purpose A Review of The Narnia
: Venus (Love, life, and the birth of worlds). The Last Battle : Saturn (Time, sorrow, and death). Significance and Purpose A Review of The Narnia Code - Official Site | CSLewis.com
: Luna (The Moon) (Silver, confusion, and madness).
: Mars (Warfare and chivalry, but also Mars Silvanus as a nature god).