"The Sword in the Stone" by TH White is one of my favourite children's novels.
It is the first of a four part series collectively entitled "The Once and Future King".
It's a bit like a mixture of Harry Potter and "The Lord of the Rings", and for my money it's as good as either of those series.
Soon after I left college I was asked to do a cover for "The Sword in The Stone", and here is the result.
Looking at it twenty years later I see a lot to like in this picture, but I don't know if it was ever even published.