What is the author's tone in Desert Solitaire by Edward Abbey?

Abbey's tone changes like the desert in different lights and seasons. He runs off into fanciful flights of imagination, tells the situation straight with no restriction, and describes scenes at length. At times his tone has an urgency to it, something needs to be done right now! Other times he lays back and enjoys the ride down the Colorado River. At all times he strives to be honest with himself, even to the point of admitting his desperate tears while trapped in the canyon near Havasu.