Chasing Rumor: A Season Fly Fishing In Patagonia by Cameron Chambers.
More than just fishing stories. You get some history of the fishery, a feel for the people, a feel for the terrain, and the knowledge that it's not always easy - things get in the way, things like weather, private property, stubborn fish.
Chambers has a very nice writing style and he is very blunt and forthcoming in his descriptions of people and places.
Well worth the read.