The Hachette Book Group’s new ChapterShare app lets the publisher put out excerpts from a book that can be read on an author’s Facebook page.

It launched this week with exclusive excerpts from chapters of James Patterson’s upcoming novel NYPD Red (which comes out in October), as well as Michael Connelly’s The Black Box (which is slated for a November release).

AppNewser explained how it works: “In order to gain access to the content, Facebook users must “Like” the content. Then readers can read these chapters on the author’s Facebook page. And if they like what they read, they can preorder a book from the Facebook page by clicking on icons for Amazon, Barnes & Noble, iBooks or Indiebound. Readers are also encouraged to share the link to the sample chapters with their Facebook friends.”

Michael Pietsch, Chief Operating Officer at HBG, stated: “I’ve been dreaming of this application for the past year. Word of mouth remains the greatest influence on book purchases, and ChapterShare was created to make Facebook an even more effective way for readers to let their friends know, instantly, about writers they love and great books that are coming.”