@boomerang,
Thanks for the lead. I've had trouble making out the signature at the bottom of the illustration. It looks like a portion of the signature has been cut off (the illustration looks like it has been cut to size and fit into a recess in the book cover as opposed to being printed on the cover). However, in light of your suggestion it appears it may be W. St. John Harper but I'll see what I can find under both names. Thanks for taking the time!