I can't speak for the authors of TCR, but I Know that James keeps very good track of chip sales, especially the "high-end" stuff. He contacts and is contacted by people that have the GREAT collections with regards to chip sales and quantities. If you would have seen him at the last two conventions, you would have noticed that he takes notes on things that collectors both tell him and bring to him...new finds, newly discovered issues, unique chips -- all to be included in his updated version. I believe that James' book will be a more complete and accurate presentation of values for the higher end chips. I can't wait for my copy!! Steve B