I turned to the research experts at the New York Public Library and their nationwide search for it came up with no copies.
This book is apparently a tie-in to this lengthy piece Hill did for Modern Methods.
I’d like to know if this book exists at all. I’d like to get a replica of it (not pay through the nose for the original). The claim of letters from those prominent men fascinates me and I’d like to see them with my own eyes. I don’t recall seeing any letters like those in Hill’s other works.