The Little House Books, as they are called now, written by Laura Ingalls Wilder are considered classics now. They probably had the same status when I read them in my childhood but at some point, as I read them with my own children, they came to represent something more. A link with the past or a reflection of a different era, one which had lessons to teach us; in any event more than just a book for children.
I happened to see an advertisement in a recent issue of The New Yorker for what I would describe as an adult edition of the books. Perhaps recognizing that more than a few adults wanted to re-read the books which had made an impression on them in their youth but who might feel self-conscious carrying around the books with covers that obviously denoted their juvenile market, the same books are now available in a two volume set, discreetly bound and in a case suitable for gift giving.
Now that Laura herself is long deceased, in a similar fate as the Tolkien works or Anne of Green Gables , the Little House books have become a brand in the marketplace with a niche. I know there are picture book versions and books based on recipes or foods from the series as well as sequels that have kept the series going.
Perhaps that is the ultimate tribute to an author. Except I once saw a book in the local library that involved Jane Austen being turned into a vampire. I wonder if that would make the lady 'lose her countenance'?