The Lion, the Witch, and the Wardrobe by C.S. Lewis
Modern Fantasy (Chapter Book)
The Twelve Dancing Princesses by Jacob & Wilhelm Grimm, translated by Anthea Bell and illustrated by Dorothée Duntze
Traditional/Folk Literature
The Twelve Dancing Princesses is the story of twelve sisters whose father, the king, cannot figure out how they are wearing holes in their shoes at night. The king becomes frustrated and invites any man in his kingdom to try and discover the princesses' secret- if they win they will marry their choice of his daughters and one day rule his kingdom, but if they fail they will be executed. Many men try and fail, but one day a poor soldier gets a tip from an old woman and decides to try his luck. Just before bed, the eldest princess brings the soldier a glass of wine which he pretends to drink. A short time later he pretends to sleep and watches as the princesses get head down a secret passageway to a magical underground castle. They travel to a lake where twelve princes are waiting in boats to carry them across water to the big castle where they dance for hours. Then the princes take them back across the lake and the princess climb back up the passageway into their beds. The whole time they are on this adventure, the soldier is with them unseen because of a magical cloak of invisibility. The next morning the soldier tells the king what the princesses are really doing each night and, once found out, they confess. He chooses to marry the eldest princess, and they are married that very day.
I think this book would be good when first introducing fairy tales. It has many elements of fairy tales including magic and the "happily ever after" ending. It would also be interesting to use when discussing cause and effect. You could start by discussing what happened as a result of the old woman giving the soldier a tip or what happened as a result of the soldier not drinking the wine. Then you could go one step further and ask them what would have happened if the soldier HADN'T gotten a tip from the old woman or had decided to drink the wine. It would be a neat conversation and would help them see how cause and effect affects a story.