This book is one of the funniest I've read this year. It's a whodunit mystery, a pretty good one at that, but the gem is in the delivery, character interactions, and the world-painting, literally.
The setting is a pristine National Park in Colorado... in 1920's. The author uses simple words with clever references to period -believable (if not -accurate) slangs and concepts to tell the story against gorgeous backdrop of a Rocky Mountain National Park.
Also the main character is Ace, not only because he's a tall and handsome park ranger, also because he has a character flaw, a self-serving tendency, but in a way that we all can relate to and laugh about, whimsically woven into the story.
One last suggestion: Read the Glossary. You're welcome.