The book is called Publishing with iBooks Author. You’ll have to sign up for an account with O’Reilly Media to download this, but the book is free to download in three formats: ePub, PDF or Mobi.
A special report from Nieman Reports on book publishing. It is heavy on articles about writing, but also addresses such such topics as creating and marketing e-books. A site worth visiting for anyone interesting in writing a book.
Another article from Nieman, this one about how Politico is creating a digital book during the 2012 campaign.