Arthur Fry was stuck in a sticky situation. While singing in the North Presbyterian Church choir, he kept missing cues because the bookmarks in his hymnal would fall out. What he needed, he reckoned, was a marker that would adhere to the spot, yet not damage the page when removed. Then one Sunday, while daydreaming during a sermon, Fry, 53, a chemical engineer specializing in new product development for the 3M Co. in St. Paul, Minn., had a flash of inspiration. He remembered a product a colleague had discovered during an unsuccessful experiment—instead of a superstrength adhesive, he'd come up with a low-tack glue. Racing back to the lab, Fry found the substance not quite perfect for his purposes—it peeled off easily but still left a residue on the page—but his quest was launched.

Nine months later Fry had perfected Post-it Notes, those little yellow memo pads with a sticky edge on each page—the pages press in place and then peel off for reuse. "You have to kiss a lot of frogs to find a prince," explains Fry of his success. (His other 3M projects have included shelf-arranger tape for libraries and gift-wrap bows.)

Post-it Notes are now expected to rival 3M's star performer, Magic Tape, and last year racked up sales of an estimated $45 million. But it was no overnight success. Test-marketed in four cities in 1977 as "Press & Peel," the novelty notepaper didn't catch on. "People thought it was just expensive scratch paper," says Fry. "Besides, no one wanted a sticky note."

Convinced of the paper's worth, Fry gave free samples to fellow employees and soon attracted the attention of a 3M executive who endorsed it. When the repurchase rate in Boise, Idaho in 1978 achieved a phenomenal 90 percent—50 percent is considered excellent—3M knew it had a hit.

"Everyone thinks I invented Post-its for them." notes Fry, "whether they're lawyers, doctors or secretaries. It's struck a creative note in people, and each one has found his own use."