Claude C. Hopkins is considered one of the greatest pioneers in direct marketing and advertising. He worked for a variety of companies and advertisers including Bissell Carpet Sweeper Company, Swift & Company, and Lord & Thomas advertisers. He is sometimes credited with the popularity of tooth brushing due to his advertising campaign for Pepsodent. Hopkins eventually retired from Lord & Thomas as president and chairman, and went on to write two books: Scientific Advertising (1923), and his autobiography, My Life in Advertising (1927).