Who was looking for a FISHY book- Hugh Fearnley Whittingstall's (and Nick Fisher's) book on fish and cooking is excellent, very good ideas to get your head around. I've been Gurnard-ing because of those two guys, a lovely bit of fish.
Carluccio's Mushroom book is great, great recipes and actually a fantastic identification guide. If you're armed with that and Roger Phillips fungi identification guide (pub by Collins I think) then you're well on the way....
(Almost forgot about Madhur Jaffrey, she's great. So's Ken Hom)
I was picking over a 1970's Reader's Digest 'country cooking' type book recently which was very good. Was a bit drinken so I didn't get the details.