It was hard to 'put it down' - it's that good! Don't know where this narrator has been, but glad he is now narrating audiobooks. What a voice!
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.
Already have recommend to friends.