I won this book (a signed copy!) at the Arizona Gorging premier a week ago. Considering how Zion is my favorite National Park (that I've been to) and how I had my own too-close-for-comfort canyoneering adventure in Pine Creek recently, I was pretty excited about the win. I skipped to the section about gambling in the slots, zipped through that, and then read the rest from the beginning. I'm pretty confident that I know my abilities and can match them to canyoneering routes appropriately, so the grisly accidents in that section didn't haunt me too much. I know accidents happen, but I believe in the abilities of myself and my frequent partners. The section on flash floods was the part that got my heart racing a bit more since I have an immense fear of getting caught in a slot during an unexpected downpour. My Pine Creek incident was probably not as close a call as I feared, but I was deep in the depths of the slot with a bunch of (rather slow) newbies when a steady drizzle broke out of the slightly overcast skies. Despite checking with the rangers that morning and repeatedly monitoring the forecast (both of which predicted a 0% chance of rain), the rain did not let up. I'm pretty certain my fear will keep me from attempting canyons in similar conditions in the future (especially now that I know just how unpredictable weather is in the Zion area).
So, I enjoyed the book largely because I personally know many of the specific places discussed. I can picture the landscapes and the incidents and the rescues.
I would have liked to see slightly more careful editing and maybe a little more speculation/discussion from the authors (although they consciously chose not to include that). The book could have been more engaging and probably really deserves 3 stars, but I gave it four because it kept my attention and is written about a place I love.