The Short Second Life of Bree Tanner: An Eclipse Novella by Stephenie Meyer.
So, if you've read the Twilight series, you know that Bree is the newborn vampire who "surrenders" to the Cullens at the end of Eclipse and then is destroyed by the Volturi. This short novel is her story - sort of a "day-in-the-life" of the vampire army that Victoria creates. As Ms. Meyer writes in the introduction, "you know this: it doesn't end well for her. But at least you will know the whole story." And I'll tell you, not only do you learn about Bree, but there is a major new piece of information that is revealed in this book that was not in the book Eclipse, but I suspect will be included in Eclipse the movie which premiers next week, and it affects events in Breaking Dawn as well.
I found Meyer's writing in Bree Tanner to be a lot more like The Host than the other Twilight novels. Now I liked The Host, but not every Twilight fan does. Also, I've read criticisms that the book doesn't have chapters, and indeed that feature can be annoying unless you plan to read it all in one sitting. But it's short, so deal with it.
The Short Second Life of Bree Tanner is available to read for free until July 5 at breetanner.com.