I guess I first saw the seven-volume Frank C. Brown folklore books in the library when I was just getting interested in traditional music.  Many times I’ve wished I could hear the source, not just read someone’s transcription.  Well, my wish has come true!

This is an incredible trove of music and folklore from all over North Carolina.  The collecting happened from 1912 to 1943.  The recordings started early — 1914, and there are 1460 items in all!
 
The books themselves are also available online at the Internet Archive and at other sites listed in this summary guide.  Better yet, at the library.