A full moon was rising into the black sky, lending a strange, dappled, almost spectral luminescence to the landscape, but he wasn't going to rely on the moonlight: it had the tendency to camouflage things, hiding sinkholes and gullies, and he'd learned the hard way not to trust to chance."
-- David Palmer (chapter 1)

Importance: This quote sets up the mystery of the full moon that is seen throughout the rest of the novel. The moon is immediately portrayed as an object of mystery and when things are illuminated by moonlight, it is hard to trust them as their true nature is hidden.

No animal in its right mind larger than a mouse would live in this kind of shit.
-- David Palmer (chapter 1)

Importance: This quote illustrates the condition that the monster of the story lives in. No natural animal would live in the area, showing that the monster who does prowl the area is not a part of...