e year was 1748, the place was Philadelphia, and the book was The Instructor, a popular British manual for everything from arithmetic to letter-writing to caring for horses’ hooves. Benjamin Franklin had set himself to adapting it for the American colonies. Though Franklin already had a long and successful career by this point, he needed to find a way to convince colonial book-buyers—who for the most part didn’t even formally study arithmetic—that his version of George Fisher’s textbook was worth the investment. Franklin made all sorts of changes throughout the book, from place names to inserting colonial histories, but he...