There is evidence that ancient South American Inca Indians were the first to grind peanuts to make peanut butter and that Dr. John Harvey Kellogg (of USA cereal fame) invented a version of peanut butter as a protein substitute for his older patients who had poor teeth and could not chew meat. Peanut butter was first introduced at the Universal Exposition (World's Fair of 1904) in St. Louis, Missouri, USA. In 1903, Dr. George Washington Carver began research with the peanut at Tuskegee Institute in Alabama, USA. Dr. Carver recognized the value of peanuts as a cash crop and proposed that peanuts be planted as a rotation crop in farmers' fields. This procedure was especially valuable in Southeastern United States. As farmers began to listen to this great scientist, crops began to flourish. Today, approximately half of peanuts grown in the United States are used to make peanut butter. (National Peanut Council, USA).