Guilford Press, London, 1957, illus Rosemary Cosgrave, 159 pp.
Not everyone can find the door that opens into fairyland, but the Robertson children, Rosalind, Peter and William, can. The door in the wall of Boxling Vicarage opens up and the children end up in the land of Aquilegia. There they meet two Canterbury pilgrims, who, like them, are time travellers. Eventually they find their way to the Kingdom of the Sea, and their old friends, the White Horses.