Pre-teen girls and anyone who enjoys cliche, corny romances.
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.
It sounds like she's reading some kind of list or something not a book. I don't like it much. I can't even read along with the book.