Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A Marred Effort

This could have been a great book. John Vernon obviously expended a lot of effort to weave the known facts into his novel and to create memorable impressions of each character from the small body of available historical knowledge. But John Vernon's easy slide into vulgarity as he creates the personalities and interactions of the characters was a big disappointment to me. I compelled myself to finish the book, mostly driven by my fascination for the Colorado River basin and its exploration. But being unwilling to contemplate that anyone else might wallow through the salacious bogs offensively dumped into this story, I threw the book in the recycling bin as soon as I was done.