Yes, the book was very intriguing, sexy, and unique.
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.
Slightly so, yes. I only got to skim my e-book copy briefly, but I loved that Christian Fox returned to narrate this sequel.