I now own the first two of the family Jensen. They are easy listening with good plot line.
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.
Yes. A nice read. I have enjoyed all of the Johnstone books, particularly the Last of the Gunfighter series.