Thus The Medium is the Massage: An Inventory of Effects was born, thanks to a unintentional error most McLuhan biographers sweep under the carpet. But, the legend goes, once McLuhan saw the typo, he exclaimed, “Leave it alone! It’s great and right on target!” The title of the book was suddenly open to four possible interpretations — a play on “Message” and “Mess Age,” or “Massage and “Mass Age.” The book soon came to be referred to simply as Massage. But what is most curious — and least known — about it is that it was developed explicitly for young readers, relying on graphic materials to engage younger audiences with big-idea nonfiction.