Technical books are part of it, and O’Reilly can probably do much more accurate forecasting on their titles than others do, but they still have total reach problems.

If I think of all the technical things I’ve done, there are some I’ve bought lots of books for, and others I’ve never bought a book at all, including some relatively major languages.

The article only covers data for the Big Five publishers, who are: Penguin Random House, Hachette, HarperCollins, Simon & Schuster, and Macmillan.