The Princess and the Goblin

Multiple Nebula and Hugo award-winner Le Guin contributes a new Introduction to this edition of McDonald's tale of a princess whose discovery of a secret stair at the top turret of a castle leads to a wonderful revelation.
Princess Irene lives in a castle in a wild and lonely mountainous region. One day she discovers a steep and winding stairway leading to a bewildering labyrinth of unused passages with closed doors - and a further stairway. What lies at the top? Can the ring the princess is given protect her against the lurking menace of the boglins from under the mountain?