Apple is promoting self-published works on the iBookstore. They are called “Breakout Books.”
These are books picked by Apple to be highlighted as self-published material by independent authors. They choose titles that are popular with readers. Apple will add new books to the list as they gain popularity.
The self-publishing business has grown immensely in the past few years thanks to platforms like Amazon’s Kindle and Apple’s iBookstore. Writers who previously didn’t have a means of distributing their books now have a cheap, easy way to do so.