The Legend of Sigurd and Gudrun, a volume of rare Norse epic poetry by Lord of the Rings author J.R.R. Tolkien, will be published in May, edited by Tolkien's son, Christopher, who also edited and completed 2007's The Children of Hurin.

Originally written in the '20s and '30s—before Tolkien wrote The Hobbit or Lord of the Rings—the book was in manuscript form and unpublished at the time of Tolkien's death in 1973.

The Legend of Sigurd and Gudrun tells the story of the Norse legend of Sigurd and the Fall of the Niflungs, the same legend that inspired composer Richard Wagner's Der Ring des Nibelungen (The Ring of the Nibelung).

Tolkien scholar and editor of The Annotated Hobbit and Tales Before Tolkien Douglas A. Anderson said that the publisher hasn't let out much information about the book just yet, but added that it presumably contains the two narrative poems that were mentioned in Tolkien's collected letters, which were published in 1981.

The poems were titled in Old Norse, which translates as "The New Lay of the Volsungs" and "The New Lay of Gudrun."

"They obviously concern the Old Norse legends of Sigurd and the Volsungs," Anderson said. "Tolkien's poems are written in a modernized version of a particular type of Old Norse poetic form, called fornyrthislag, which comprises an eight-line stanza."

The story of the hero Sigurd and the dragon can be seen as one of Tolkien's primary inspirations. A number of elements of the dragon Fafnir—the craftiness, the malice and other traits—can certainly be seen in the dragon Smaug in The Hobbit, Anderson said.

Very few people have read the poems—not even Tolkien scholars like Anderson—as until now they've been part of the unpublished Tolkien materials that are not available to the public.

"The poems in The Legend of Sigurd and Gudrun ... were completed entirely by J.R.R. Tolkien many years ago and are part of another type of writing that he did, remolding or translating the medieval works that he worked on as a scholar," Anderson said.

"Tolkien is also known to have completed a prose translation of Beowulf, as well as writing a large part of another poem called 'The Fall of Arthur,' which is in modern English but uses the medieval technique of alliterative verse. ... Neither his translation of Beowulf nor his unfinished reworking of the King Arthur story have been published, so perhaps we can look forward to these in the future."