It’s called Quarantine, and it’s about this guy who climbs up a cliff in the desert to live in a cave for 40 days, because he thinks someone told him it was a good idea. Most of the book focuses on some other people who are also out in the desert taking the 40 day cure, but also-let’s be practical here-with a better plan for coming out of the ordeal alive. One of these people is a traveling salesman with the gift for gab & he susses out what the guy in the cave is up to, and after the 40 days are up, goes out into the world to tell people who will listen about all the things he has made up about the dead guy in the cave
It is a very good book.