A fictional book is a story that someone made up in their head and wrote down on paper for others to read. It's like a big pretend game that you play inside your head, and instead of just telling someone about it, you write it all down so that others can experience the story too. Sometimes the stories are about real things or places, but the details and characters in the story are all made up. Reading a fictional book is like going on an adventure in your mind, where you can imagine all sorts of things happening that might not be possible in real life. It's like having your very own movie playing in your head that you get to imagine and picture all by yourself!