The most comprehensive definition of the harp guitar:
What Is a Harp Guitar? by Gregg Miner, the "Harp Guitar Pope."
Wade, the traditional closing song for the Harp Guitar Gathering concerts is "The Water Is Wide." Here's a video from Harp Guitar Gathering 5. Unfortunately, the sound is such that you can't really hear the harp strings.
http://www.youtube.com/user/GMiner#p/u/36/pawgzVGC9-4
Also, what a keen eye you have. It is indeed a Knutsen, and it is all koa, single piece top and back. Imagine what koa that size would sell for now... As I'm sure you all know (
), Chris J. Knutsen not only invented the American harp guitar (and licensed his design to the Larson Brothers), he also created the Hawaiian guitar (and then taught Herman Weissenborn how to make them).