Liz

The SAS Guide and Ray Mears are OK, but the book you must absolutely get is "Food for Free" by Richard Mabey, published by Collins.
It's UK / Europe based has been constantly in print with eleven revisions since 1972 and lists all manner of wild foods and recipes. The photos are superb - and best of all they've just bought out a pocket version of it that I snapped up immediately.

Good Luck, Scott