The Crystal Cave
by Mary Stewart
Buy on AmazonThe Crystal Cave is a 1970 fantasy novel by Mary Stewart. The first in a quintet of novels covering the Arthurian legend, it is followed by The Hollow Hills.
Recommended by
NPR Top 100 Science Fiction & Fantasy Books (2011) · npr.org
"I recently reread "The Crystal Cave" — again. Her skill with language and characters, at blending romance and suspense, transcends time."
By the Book: Nora Roberts · nytimes.com