In 1968, Dr. Spencer Silver invented a repositionable adhesive that was strong enough to stick to surfaces but did not leave any residue. Arthur Fry first invented the Post-it Note in 1974 while looking for a bookmark. Fry took some of Silver's adhesive and applied it to the edge of a piece of paper and solving his problem.
Post-it notes (a registered trademark of the 3M Company) were invented by 3M's Art Fry, using an adhesive developed by a colleague, Spencer Silver. Until the patents ran out in the '90s, all such notes were produced at the 3M plant in Cynthania, Kentucky. Since the patents expired, however, many other companies throughout the world now make similar repositionable adhesive note pads.