The author's son, Christopher Tolkien edited the translation of his father's "enter[ing] into the imagined past" of the heroes. Christopher said his JRR -- who also wrote The Lord of the Rings and The Hobbit -- "seems never to have considered" publishing the translation.
The book will also include a series of JRR's lectures about the poem given by him when he taught at Oxford during the 1930s.
Chistopher said his father's incredibly descriptive tale makes it seem like "he entered into the imagined past: standing beside Beowulf and his men shaking out their mail-shirts as they beached their ship on the coast of Denmark, listening to the rising anger of Beowulf at the taunting of Unferth, or looking up in amazement at Grendel's terrible hand set under the roof of Heorot."
Beowulf, the longest poem written in Old English, dates back to the 11th century. It consists of 3182 alliterative long lines and the single surviving manuscript is kept at the British Library in London.
HarperCollins will publish Beowulf: A Translation and Commentary on 22 May.