Hi Renee. I'm Bill Pfaffenberger from Avon, IN and I think that I have the information for you. Your grandfather Robert's father (your great grandfather) was Ferris Newton Pfaffenberger. He was a brother to Clarence J. Pfaffenberger who was the author of "The New Knowledge of Dog Behavior." You are a descendant of Andrew Pfaffenberger who brought his large family to America in 1837. I have written a small book on Andrew and his offspring. You linage to Andrew is as follows: Andrew => John Conrad => Newton J. => Ferris Newton => Robert => Your father. My chapters on Andrew and then John Conrad will fill you in on the early history. Here is the link to the information:
http://www.pfaffenberger.org/pfaffenberger_history.htm