This simple children's fantasy from the 1800s is a good introduction to the fantasy genre. It is a forerunner of books like C. S. Lewis' Narnia series and J. R. R Tolkien's Lord of the Rings. It may not be for everyone.

The story is rich with easy-to-understand spiritual symbolism. As a family read-aloud or audio listen, you can help your children learn how to pick out symbolic spiritual elements and truths. 

Characters include the evil hobbits who live underground, the Princess Irene and her Papa-the-King, Curdie-the-miner's-son, and Irene's wonderful great, huge Grandmother Upstairs whom not everyone knows about or believes in. The ending includes a fairly prolonged account of a battle with the goblins who try to kidnap Irene. 

This book is in the public domain and can be read for free at https://www.gutenberg.org/ebooks/708.