Tom:
"The books were, I presume, written a while ago."
Over the last few years we have added to our collection A History of European Folk Music (1997), the completed set of The Greig Duncan Folk Song collection (8 vols. - 1981-2002) and Folk song tradition, Revival and Re-creation (2004).
Shortly we will be receiving the latest copy of The Folk Music Journal from the English Folk Dance and Song Society (1899 - ongoing)
If anybody asked me for my definition of Folk music I would refer them to the 1954 one; if they wanted it in more detail I would give them the one from the Funk and Wagnall Standard Dictionary of Folklore, Mythology and Legend; and if they wanted a fuller explanation I would hand them a copy of A L Lloyd's Folk Song in England. If I wished to put it into a social format I would give them David Buchan's The Ballad and The Folk. These are the circles you have to square to call yourself 'folk'.
I still don't know how you are going to resolve the copyright/public domain dilemma - or doesn't it concern you?
Q   "Why folk clubs are dying"
A   "if we can find two or three others of a like mind to sing and play together and not slag each other off for forgetting words or other seemingly unforgivable misdaminors."
Jim Carroll