"The two most powerful words you can use in a headline are FREE and NEW. You can seldom use FREE, but you can always use NEW."

So says ad man David Ogilvy in his 1963 tell-all Confessions of an Advertising Man. Still considered the de facto guide on modern advertising, Confessions lays out in fine print the strategies the door-to-door salesman turned "Father of Advertising" used to create Ogilvy & Mather, one of the most successful ad agencies in the world.

The book was inspired by Ogilvy's belief that his industry faced systemic problems in 1963: Manufacturers spent more money on price-off deals than solid advertising while agencies were more interested in awards than products. The solution, Ogilvy contended, relied on research, discipline, creativity with an emphasis on the "Big Idea," and most importantly, results. "In the modern world of business," he wrote, "it is useless to be a creative, original thinker unless you can also sell what you create."

Ironically, the master of American advertising was British-born -- an Oxford-educated historian who had come to the U.S. to work for Gallup before starting his own agency. Ogilvy's zeal for research proved a big-seller when it came to advertising: He preached that a copywriter should both know and believe in the product. For his part, he writes in Confessions, "At breakfast I drink Maxwell House coffee or Tetley tea, and eat two slices of Pepperidge Farm toast. I wash with Dove, deodorize with Ban, and light my pipe with a Zippo lighter." The results? Well, his slogan "Cream Your Skin While You Wash" made Dove the top-selling soap in the U.S.

Confessions of an Advertising Man was no less successful as the book sold one million copies and was translated into fourteen languages. In 1983 Ogilvy wrote a second volume, Ogilvy on Advertising -- essentially a reiteration of the first. Why not write something completely new? "If you are lucky enough to write a good advertisement," he advises in Confessions, "repeat it until it stops pulling." (Especially if you can say it's NEW.)