As already mentioned previously it's prohibited to fish for Eels in Scotland, and illegal to take them for the pot by rod and line in England and Wales. They're cited as critically endangered.
more info on Eels and Eel fishing at http://www.nationalanguillaclub.co.uk
Ahh, fishing books!
Few suggestions.
Fenland Pike - Moules and Barrett
The Eel Angler - McConnell
Pikers Progression - Watson
Anything by Yates.
and my current favorite, A Dream of Jewelled Fishes, John Aston