Dark Disciple. James Luceno did a fantastic job, as always. He authored one of my favorite Star Wars Legends novels, Star Wars: Darth Plagueis.
I was pleasantly surprised that this story began during the Clone Wars. The story of Galen Erso and Orson Krennic was interesting, and there were definitely a few surprising along the way. After listening to this novel, I am more confident that Rogue One will be a great film.
I also think I may try to listen to Tarkin again, I listened to it, when it was released in November of 2014, and I think a refresher might be in order, before Rogue One to comes to a theater near me
If you're new to Audible, you can sign-up for a free trail that includes two free audio books. A great choice for the second free audio book is Tarkin. Sign-up today.