Why is Brunnhilde so angry? Many have tried -- Wagner and English poet William Morris among them -- to explain what made the most famous Valkyrie of Norse legend rage against her beloved Siegfried, but it's an enduring mystery: The eight pages of the Codex Regius of the Edda, a major source for that part of the Nibelung legend, were torn out long ago and lost.
J.R.R. Tolkien also sought to fill in this gap, and in the scholarly hands of his son Christopher, those efforts have been published as "The Legend of Sigurd and Gudrun" (Houghton Mifflin Harcourt: 378 pp., $26). Though it may not be to everyone's taste, Tolkien fans should make room for this serious philological effort on their shelves. Not only is his explanation for Brunnhilde's (here Brynhild) wrath interesting (no spoilers), but one also sees how this epic may have inspired his own literary creations. In reading about Andvari and his magical ring -- "(The Dwarf spake darkly / from his delved stone:) / 'My ring I will curse / with ruth and woe!' " -- Middle-earth seems not so far away.