There is a book: Dorothy Knapp Philately And Family by Douglas S. Weisz that might prove useful to your search if you don't get any answers. Bruce
Hi, Can someone tell me what was Knapp's: 1. first HDHP (not add-on); 2. first FDC cachet design (for a FDC manufacturer) Thanks for your help
re: Dorothy Knapp First Day Covers