 Starting in 1974, Parker Brothers and its then corporate parent, General Mills, attempted to suppress publication of a game called "Anti-Monopoly", designed by San Francisco State University economics professor Ralph Anspach and first published the previous year.Anspach began to research the game's history, and argued that the copyrights and trademarks held by Parker Brothers should be nullified, as the game came out of the public domain.Among other things, Anspach discovered the empty 1933 Charles B. Darrow file at the United States Copyright Office, testimony from the "Inflation" game case that was settled out of court, and letters from Knapp Electric challenging Parker Brothers over "Monopoly".