
David Ogilvy:
Ogilvy’s ad for Rolls-Royce remains the most famous automobile advertisement of all time. The company was on a particularly tight budget, and Ogilvy was asked to perform the impossible: create an ad that people would read...and never forget. Ogilvy achieved the impossible with one simple sentence: “At 60 miles an hour the loudest noise in this new Rolls-Royce comes from the electric clock.”
The Rolls-Royce ad is yet another tribute to Ogilvy’s background in research. He inundated himself with data on the Rolls-Royce, which eventually became the basis for most of the copy in the ad. “The famous headline came from a specific, obscure piece of testing data from the factory -- a triumph, despite the ad's reputation as a creative milestone, of Ogilvy's faith in research.”
Leo Burnett:

He was not the adman's adman. He wasn't a hipster like William Bernbach, who tapped into youthcult with the "Think Small" campaign for Volkswagen. He wasn't an elegant rational
ist like David Ogilvy, whose ads famously advised the rich that a Rolls-Royce was the sensible car to buy. He didn't even work on Madison Avenue, but in Chicago's Loop instead. But Leo Burnett, the jowly genius of the heartland subconscious, is the man most responsible for the blizzard of visual imagery that assaults us today.