I second the recommendation for Hill, a very nice book. I also like Anthony Crossleys "Floating line for salmon and sea trout". I also liked the compilation of stories in the recent book "The Leaper". Another thing I like to read in winter is Ernest Schwieberts short stories on salmon fishing, if you ever plan on fishing a west coast Norwegian river you should read the story "Raspberries in the rain".
If anybody can read Norwegian/Swedish/Danish it's also worth it to look for any of the latest books by Jan Johansson, particularly "Du vidunderlige lakseflue" which is a nice book on flies, Norway and Scotland.
I see that I need to read Philip Green in english. I have only read the Norwegian translation, and I did not like that very much.