In 1947, Frances Gerety, a copywriter on the De Beers account at N.W. Ayer & Sons in Philadelphia, Pennsylvania, created a phrase that has become iconic: “A Diamond Is Forever.” In 1999, Advertising Age named it the Slogan of the Century. Today, it’s a line on the lips of many in the industry — not as a wistful longing for the past, but as a reminder of a successful generic campaign that d...