"Eels" by John Sidley (Coch-Y Bonddu Books) is a little dated in places, but a must read for any serious eel angler. More recent is "Eels: The Final Frontier" by Steve Ricketts. Brian Crawford's books are interesting, but collectible and expensive. For a real insight into the species "The Eel" by E W Tesch, and Chris Moriarty's "Eels; a Natural and Unnatural History" are very good, and can be found at a reasonable price on the "net". The National Anguilla Club site at The National Anguilla Club (NAC) - The Eel Specialist - Eel Fishing is also useful, and joining gives access to the forum, and loads of help if you are serious about eels.
Hi mark, sorry for the delayed reply haven't logged in for a while, thanks for the advice i shall definately look into getting them and joining the NAC.