By best friend is graduating high school next week, and I wanted to get something special for him. We've been treasure hunting together for the past two years, and since he is planning to go to Colorado at the end of the summer to work on his FFL, I thought a book on lost treasures in Colorado would be a great graduation gift for him. The problem is, there are several to choose from, and I'm not sure which one would be best. Anyone have any suggestions?