Discover Series Books for Babies & Toddlers It's time for kitty cat dress up! These cute kitties put on their best in this Discover Series Picture Book. CATS IN COSTUME features more than 25 cats in a wide range of costumes. Babies and toddlers will love swiping through the simple and colorful photos while older children can't help but laugh at a cat in a mouse costume. Use this photo dictionary as a learning tool. Each photo has a clear title beneath it for identification. Language learners, children, and people looking to build their vocabulary can use this simple book to learn new words.