There are 2 books in the A Tale of Barque Cats series. The newest book is Catacombs which came out in 2010.

1
Catalyst

By Anne McCaffrey , Elizabeth Ann Scarborough ,

Book cover of Catalyst
Pilot, navigator, engineer, doctor, scientist—ship's cat? All are essential to the well-staffed space vessel. Since the early days of interstellar travel, when Tuxedo Thomas, a Maine coon cat, showed what a cat could do for a ship and its crew, the so-called Barque Cats have become highly prized crew members.…
When you buy books, we may earn a commission that helps keep our lights on (or join the rebellion as a member).

2
Catacombs

By Anne McCaffrey , Elizabeth Ann Scarborough ,

Book cover of Catacombs
In Catalyst, award-winning authors Anne McCaffrey and Elizabeth Ann Scarborough introduced readers to the beguiling Barque Cats: spacefaring felines who serve aboard starships as full-fledged members of the crew. Highly evolved, the cats share an almost telepathic bond with their minders, or Cat Persons—until, suddenly, there is no “almost” about…