Claude Hopkins invented it. Devoted an entire book to it, “Scientific Advertising”, 1923.
Rosser Reeves, famous as the inventor of the “Unique Selling Proposition”, talks about it at length, how to do it and why it is crucial, in “Reality in Advertising”, 1960.
David Ogilvy heavily promoted it as essential to success, in “Ogilvy on Advertising”, 1983.
Sergio Zyman considers it so lost and so essential it is one of the two main themes in his book “The End of Marketing As We Know It”, 1999.
SO WHY DON”T MORE MARKETERS DO THEIR HOMEWORK, RESEARCH, SURVEYS, TEST AND MEASURE?
Beats me.