The powerful legends upon which Wagner build his ""Ring""cycle are the foundation of this historical fantasy in three books by Grundy -- a first novel of epic proportions. The story is essentially the saga of Sigifrith (Siegfried; Grundy's renderings of the characters' names may briefly disorient readers who know them in the Norse variants used by Wagner), the quintessential hero of the Germanic tribes. The first book presents Sigifrith's background in the form of a vision, telling him of his heroic ancestry and of the cursed treasure guarded by the dragon Fadhmir. The second book tells of his coming to age, gaining a steed and a sword worthy of a hero, and of his deeds -- revenging his father's death, slaying the dragon, and taking possession of the treasure. In the third installment, his tragic destiny faces him with an impossible choice between two women: Gundrun, a powerful king's daughter, his betrothed; and Brunichild, who believes herself to be his destined soulmate. Grundy sets his epic in the historical fifth century, portraying the customs of the early German tribes in great detail. The author sometimes lets his interest in the anthropological background distract him from storytelling, but the momentum of the plot is usually strong enough to carry the reader past these slow spots. Meanwhile, the prose rarely rises to epic heights, but, on the other hand, it rarely falls flat; at his best, as in those scenes where supernatural forces intrude upon the human stage, Grundy effectively evokes the sheer alienness of the culture he describes. A workmanlike retelling of one of the great tales, full of imaginative sidelights on the people who created it.