Claude C. Hopkins (1866-1932) was one of the great advertising pioneers, he believed advertising existed only to sell something and should be measurable and justify the results that it produced.He worked for various advertisers, including Bissell Carpet Sweeper Company, Swift & Company and Dr. Shoop's patent medicine company. At the age of 41, he was hired by Albert Lasker owner of Lord & Thomas advertising in 1907 at a salary of $185,000 a year, Hopkins insisted copywriters researched their client products and produce reason-why copy. He believed that a good product was often its own best salesperson and as such he was a great believer in sampling.To track the results of his advertising he… used key coded coupons and then tested headlines, offers and propositions against one another. He used the analysis of these measurements to continually improve his ad results, driving responses and the cost effectiveness of his clients advertising spend.His classic book, "Scientific Advertising," was published in 1923, following his retirement from Lord & Thomas, where he finished his career as president and chairman. He died in 1932.