Orlando the Marmalade Cat: A Camping Holiday by Kathleen Hale
This is the first book about Orlando, the famous marmalade cat. He and Grace, his beautiful tabby wife, have three kittens - tortoiseshell Pansy, white Blanche and coal-black Tinkle. In this first story Orlando and his family go off on a camping trip where the kittens learn to swim, paint pictures of the scenery and enjoy sleeping (or not sleeping) under the stars.