Nothing fuels the fires of nostalgic fly-fishermen quite like a fishing log.
There are personal logs, and there are those old books that the farmer keeps for his water. The one for which he calls you into the light of his kitchen, to fill-in before you depart.
They may be leather bound, or maybe just a simple book from the stationer in town, but either way the book will be tatty from age and use. And if it is not yet a little yellowed , just give it time.