3M invented the Post-it Note, first marketed nationally in the United States in 1980.
The product grew from two separate discoveries at 3M. In 1968, scientist Spencer Silver developed a pressure-sensitive adhesive that stuck lightly and could be removed. In 1974, colleague Art Fry imagined using that adhesive for bookmarks that would stay in a church hymnal without damaging the pages.
3M first tested the notes under the name Press 'n Peel in several U.S. cities in 1977. The company refined the product, renamed it Post-it Notes, and launched a national U.S. marketing campaign in 1980. Canada and Europe followed in 1981.
The familiar yellow color was not part of the original scientific breakthrough. It was selected partly because the laboratory had leftover yellow paper available for testing. Post-it is a 3M trademark, and the notes later expanded into many colors, sizes, shapes, and adhesive products.