Thanks Sandra, it appears I did Mr Ives an injustice. The book contains no evidence of his involvement other than on the cover, and I assumed it was just a marketing ploy by the publishers.

I have a soft spot for it, as it is the book which 50 years ago turned me on to folk music, in which I had no previous interest. I found it in my local music shop and bought it for the sole reason that it contained chords which, as a novice guitarist, I could play.