Over Sea Under Stone by Susan Cooper [FIRST EDITION]
US FIRST EDITION  HARCOURT, BRACE & WORLD
11th printing. Hardcover with dust jacket.
Dust jacket is excellent but has a few spots of discoloration on back and a bit on underside Book itself is excellent & reads like new!
Illustrated by Margary Gill. On holiday in Cornwall, the three Drew children discover an ancient map in the attic of the house that they are staying in. They know immediately that it is special. It is even more than that -- the key to finding a grail, a source of power to fight the forces of evil known as the Dark. And in searching for it themselves, the Drews put their very lives in peril. This is the first volume of Susan Cooper's brilliant and absorbing fantasy sequence known as The Dark Is Rising.