Claude Hopkins (1866-1932) was a pioneer who wrote the groundbreaking book Scientific Advertising. He developed the concept of "reason why" advertising. He first cut his teeth designing ads for the Bissell Carpet Sweeper Company.
Helen Lansdowne (1886-1964) was a famous copywriter known for her work for Woodbury's Facial Soaps and Pond's Cold Cream. She was the first woman to present ads to the board of Procter & Gamble.
Raymond Rubicam was the co-founder of prodigious ad firm Young & Rubicam. He managed to get pollster George Gallup to join Y&R, where he formed the first advertising research department.
Rosser Reeves (10 September 1910–24 January 1984) Was a hugely successful American advertising executive and pioneer of television advertising. He believed the purpose of advertising is to sell. He insisted that an advertisement or commercial should show off the value of a product, not the cleverness of a copywriter. His most typical ad is probably that for Anacin, a headache medicine. The ad was considered grating and annoying by almost all viewers but it was remarkably successful, tripling the product's sales. In 7 years the 59-second commercial made more money than the movie Gone With The Wind had in a quarter-century.