Arthurian sources hold little material on Merlin's childhood and youth. Barron has drawn on Celtic mythology for many of the colorful details about the "halfway-between" land of Fincayra. Of these, the two most likely to be familiar to readers are probably the spinning castle (also called the Shrouded Castle) and the Cauldron of Death.

The inaugural issue of a leading fantasy magazine (Marion Zimmer Bradley's Fantasy Magazine, 1989) featured a story about a spinning castle. The Cauldron of Death which takes people into the Otherworld is a presence in Celtic religion. It is a darker parallel to the cauldron of plenty; both have connections with the witch's cauldron of popular folklore.

In structure The Lost Years of Merlin is a classic hero's quest, although Emrys is younger than the usual protagonist of such tales. Those familiar with the work of Joseph Campbell or Christopher Vogeler will recognize...