A book dealer contacted me asking if I was in any way connected to the caricaturist who produced this:
I certainly wish I could draw hands as elegantly as that. Obviously it's not me, as this is from the 1930s! There is some similiarity in the signatures, but I think it looks more like "Ronson", with an elaborate "s", or it could be "Royson".
Google searches have failed to turn up any info on this artist, so if anyone knows anything about "Ronson" or "Royson", please let me know and I'll pass it on.