Lewis, C.S. "The Lion, the Witch and the Wardrobe" (first of the Narnia Chronicles) - 1950
I read this book years ago with my children. Since I am not a big fan of fantasy and even less of stories where a couple of children save the world, I was happy that they read the following ones on their own. Although, I have to say, this book was very good. It almost reminded me of fairy tales that I quite like. They usually show a lot about a people's character, their values and myths.
So, I would definitely recommend this book to children and anyone who likes fantasy stories, should be one of the first books for them to read.
From the back cover:
"Lucy has stumbled upon a marvellous land of fauns and centaurs, nymphs and talking animals. But soon she discovers that it is ruled by the cruel White Witch, and can only be freed by Aslan, the great Lion, and four children…"