The Cat Who Played Post Office
Three of the best from prolific American whodunnit writer, Lilian Jackson Braun. The stories feature Jim Qwilleran, a journalist, and cats, such as Koko the Siamese.
These are enjoyable adventures which have great appeal to cat lovers, and are gripping enough to appeal to whodunnit lovers who aren't cat mad.
While these aren't 'deep' novels, they do tell us a lot about how certain people live in America, and they are good books to relax with.