 Mattson first started his career in public relations as an assistant advertising manager for the Bristol Company, then went to work for Bell Telephone Laboratories as editor and technical information supervisor.After his work at Bell, Mattson worked as an associate editor for "International Science and Technology" and then worked as director of corporate public relations for Monsanto Company in St. Louis, Missouri.Mattson would remain with Monsanto until 1973 when he joined IFT.