There are three books for children that have been purchased at least 100 million times. The bestselling is Antione de Saint-Exupery's Le Petit Prince, published in 1943. The second bestselling is J. K. Rowling's Harry Potter and the Philosopher's Stone, published in 1997. The third bestselling is J. R. R. Tolkien's The Hobbit, published in 1937.
All three of these books fall into the fantasy genre, and all three were published from the mid-twentieth century onward. But while it sometimes seems like children's fantasy and its popularity is a distinctly modern phenomenon, fantasy books for children conforming to what we would recognize as the modern conventions of the genre actually emerged around 150 years ago. While none of these early fantasy books have sold even 15 million copies each, without them the genre fantasy genre--and therefore some of the most successful books of all time--simply wouldn't exist.
In this article, I've shared some of the best and most important early modern fantasy books for children, covering books from around 1870 to around 1920. All of the books featured are currently in the public domain, so they are free to read, share, and study, but I've avoided repeating any of the books featured in Sparrow Tree Square's Great Public Domain Children's Books article.
I hope that this article encourages fans of modern fantasy to take a look at the books that forged the way for their favorite contemporary authors, and that it fosters a new appreciation for these less successful but more groundbreaking works in the children's fantasy genre.