folks
found a few old books archived & available to read online or as PDF docs & more. free!
Among them, there's a great book by Alexander Mackie, 'The art of worm-fishing, a practical treatise on clear-water worming (1912)' -
http://www.archive.org/details/cu31924003697962 - he talks about fishing the Don & Deveron. Some great reading (although the reports of taking home 14lb of weight of trout per day makes me gasp!). A cracking chapter on the technique - substitute the worms for upstream spiders or weighted nymphs, and the technique & approach still applies.
He's also written a book on Aberdeenshire - interesting for a wee bit of history.
If you also search on 'trout fishing' there's 140 or so books - even a few treatises on maoriland (!!) for Mike Barrio...
http://www.archive.org/search.php?query=subject%3A%22Trout+fishing%22something to read while the river is flooding...