A pleasantly lilting, somewhat simplified rendition of an Irish tale about a boy and his magical companion: a bull that, dying in battle, leaves the lad a sword and a tablecloth, both with unusual qualities. Before he meets the inevitable princess Billy escapes an evil stepmother, kills three giants, and—``after a terrible fight entirely''—slays a dragon, losing a shoe as he leaves the field. The princess finds it, and...well, that part of the story's familiar too. Root's illustrations twine vigorously around blocks of text, opening to full-page scenes and spreads to capture climactic moments: the bull's death (which has the swirling intensity of a painting by William Blake); Billy's hair standing comically on end when he hears the first giant's roar; the happy couple sharing a goblet at their wedding feast as king and queen drowse contentedly on either side. Greene pays fine tribute to her source, shanachie Seumas MacManus, in a prefatory note. (Folklore/Picture book. 6-8)