http://www.nytimes.com/2010/01/24/magazine/24patterson-t.htm...
Here's the section:
"WHAT IS PERHAPS most remarkable about the Patterson empire is the sheer volume of books it produces. The nine hardcovers a year are really only the beginning. Nearly all of those books are published a second and third time, first as traditional paperbacks, then as pocket-size, mass-market paperbacks. “Scarcely a week goes by when we aren’t publishing something by James Patterson,” Young told me, only half-joking."
Another fiction example, to ensure the last book of the Wheel of Time would hit #1 on the NYT hardcover list the original author's widow talked the publisher into not releasing the eBook right away to make sure people who bought the book week 1 got the hardback ensuring it would hit the top spot.
This was in the 90s but similar principles are probably true in a lot of fields.