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:
: Luna (The Moon) (Silver, confusion, and madness). The Narnia Code: C. S. Lewis and the Secret of ...
: Mars (Warfare and chivalry, but also Mars Silvanus as a nature god). The Narnia Code: C. S. Lewis and the Secret of ...
