Perhaps even more interesting is that books sold on the Kindle are now outpacing the hardcover books Amazon sells. In the past three months, for every 100 hardcover books sold, Amazon.com has sold 143 Kindle books, they say. And that gap is getting wider. In the past month, for every 100 hardcover books sold, there have been 180 Kindle books sold through Amazon. This is across Amazon’s entire U.S. book business and even includes hardcovers that have no Kindle version.

Mark your calendars, friends and neighbors. This is a Gutenberg moment.