There are many reasons why a book might be unavailable.
Sometimes a book goes temporarily out of print - and sometimes no audio version has ever been recorded. Audible wants to give you the most complete selection we can and we'll keep adding series and filling in gaps as quickly as possible.
Well written and read.
I have no particular problem with very gruesome novels, but this novel is not very good. The narration, on the other hand, is superb.