Discover Series Books for Babies & Toddlers Every princess needs a castle and every knight needs a fortress to defend. In this Discover Series book, young children can learn the proper terminology for castles and explore the crisp and clear photographs with simple titles. Used as a jumpstart for interaction, Discover Series Picture Books are a great way to introduce new images, words and ideas to kids. | Castles by Xist Xist Publishing, Paperback | Indigo Chapters