I recently found out that this book is available. I sent an e-mail to Rosalie Haines inquiring about purchasing the book. I know there are many Jackson County people who are descendants of the Venne immigrants. This is what Rosalie sent me:

Dear Cindy,
We recently found out that the Hamilton County Genealogical Society of Ohio will be selling Udo's Thoerner's book "Venne in America".
The HCGS is a chapter of The Ohio Genealogical Society (OGS). Hamilton County Genealogical Society, P.O. Box 15865 Cincinnati, Ohio 45215-0865
Telephone; 513.956.7078 ...
Website: hcgsohio.org/
The price is $28 + postage. If you go to their website you will be able to contact them via email and perhaps place your order. The books still have to be sent to the HGCS from Germany and it may take 2 to 3 weeks before they are available.
Rosalie Haines