Over Sea, Under Stone by Susan CooperRead about the other entries on the list.
The first in the Dark Is Rising series that chronicles the battle between the forces of Light and Dark, this family adventure story starts with a hidden door behind which the Drew children discover an ancient document. The document, written in Latin and Early English, points to the existence of a grail and foretells the return of Arthur Pendragon if it is ever brought to light. Cooper is working in darker territory than Blyton, blending Arthurian myth with genuinely unsettling intimations of the evil that she develops more fully in the rest of the series. Her books are deeply embedded in the landscapes and legends of Wales and southern England; here the children must decipher the clues of the Cornish coastline itself – its standing stones and rocky headlands – in their quest to find the grail before it can be claimed by the agents of darkness.
--Marshal Zeringue