You know, there's really no reason to repeat the second 'Light' in the back cover (or second 'Dark' for that matter). It is perfectly good just as 'Light Spells' (or 'Dark Spells', depending on book orientation).

So I'm thinking 'Aha! This might be a clew!'. If 'Light' spells out 'Light', that suggests a letter-substitution cryptogram in which some letters equal different letters, while other letters are left alone. The letters for 'Light' occupy the inner nine spaces of a Q-Less 5x5:

X-X-X-X-X-
X-G-H-I-X
X-L-M-N-X
X-R-S-T-X
X-X-X-X-X

The words sight, might, night, right, tight, etc., presumably can all be assumed as correct. The outer ring of 16 letters, however, may be subject to change, as in some sort of rotation. "Light Spells Light" ought to mean something, afterall.

Perchprism