Have you heard of Palmolive? What about Pepsodent? You surely have – but have you heard of Claude C. Hopkins, the man whose advertising campaigns made both brands into household names?

Since its original publication in 1923, Claude Hopkins’ classic book Scientific Advertising has been a must-read for students of advertising, copywriting, and marketing. Testing and measuring formed the foundation of Hopkins’ advertising approach, and they haven’t lost their importance in the age of Google AdWords and social media marketing.

Scientific Advertising has influenced countless leading advertisers and marketers, including David Ogilvy, Gary Halbert, and Jay Abraham. Ogilvy, widely considered the “Father of Advertising,” wrote that “Scientific Advertising changed the course of my life,” and Halbert recommended the book as the most essential starting point for new marketers.