Here’s a timely slice of publishing history from Michael Korda’s book, Making the List:

[Before World War Two] the mass-market paperback business was still in its infancy. The war decade to come would change that. Pocket Books had been founded in the thirties, to sell books at twenty-five cents a copy. These paperbacks were distributed by magazine wholesalers to drugstores, candy stands, and news stores, but bookstores as such didn’t carry them, or even acknowledge, for the most part, their existence. Pocket Books soon had plenty of rivals in the paperback business, which was already fiercely competitive and fast growing, but it would take the war, when millions of men had time on their hands to read, in training camps or on troop ships, and millions of women were at home, waiting for their return, to make the mass-market business really take off, and indeed, for a time, to achieve dominance over the hardcover book business.

Successful mass-market paperback titles sold in the millions of copies, dwarfing the numbers sold in hardcover by conventional booksellers. . . . In short, after the Second World War, there would be two different book markets: the “mass” market of paperback publishing, which mostly sold in outlets other than bookstores, and the conventional hardcover book business, centered on the bookstore, which, despite the growing help of the book clubs, sold fewer books, but at much higher prices (from page 76).

The how of publishing is in constant flux. The what and why remain constant. People love to read. The key for publishers is learning to think like readers.