Aurelian is due to be released in September, so it is getting very close. Not to mention that the artwork for its cover is absolutely amazing. Check out the cover art by Neil Roberts.
Aurelian is a limited edition Horus Heresy novella by Aaron Dembski-Bowden from the Black Library. The book becomes available Sept 12th at 6pm (BST) and is strictly limited to 3000 copies. The cost is $50.