This is a great book, and IMHO, a must read for anyone who travels the parks, especially fisherman.  It is very informative (almost to informative, making it a little hard to follow) on the different niches in the wilderness.  For fisherman to read they would get a LOT better understing of just how FRAGILE the underwater ecosystem is and how vulnerable it is to overfishing.  Please, I incourage everyone to at least thumb through this one.