Post-it note
The product for which he is best known, however, was born in the 1970s. Fry attended a seminar given by another 3M scientist, Spencer Silver, on a unique adhesive Silver had developed in 1968. Silver's innovation had an unusual molecular structure, yielding a glue strong enough to cling to objects but weak enough to allow for a temporary bond. At the time, Silver was still searching for a marketable use for his invention.
As the legend goes, Fry was in church when he came up with the perfect application. Fry sang in his church choir on weekends, and he used slips of paper to mark the pages of his hymnal. When the book was opened, however, the makeshift bookmarks often moved around or fell out altogether. On a Sunday in 1974, it occurred to him that Silver's adhesive could be put to use to create a better bookmark. If it could be coated on paper, Silver's adhesive would hold a bookmark in place without damaging the page on which it was placed.
The next day, Fry requested a sample of the adhesive. He began experimenting, coating only one edge of the paper so that the portion extending from a book would not be sticky. Fry used some of his experiments to write notes to his boss. This use led him to broaden his original idea into the concept that became the Post-it note.