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.
No. Harrison is horrible. Had I noticed who was reading before I spent the credits I never would have downloaded this book.
I love this series but this one I couldn't get into. The story fell flat.