Beowulf is the longest poem that has come down to us from Old English. It is seen as an encomium, a song of praise for a great king: "Hwæt! We Gardena in geardagum þeodcyninga þrym gefrunon hu ða æþelingas ellen fremedon." In modern English: "Lo! We the Spear-Danes, in days of yore, have heard of the glory of the people's kings how the noble ones did deeds of valor."

Old English poetry such as Beowulf is very different from modern poetry. It was probably recited, for few people at that time were able to read. Instead of pairs of lines joined by rhyme (similarity of sounds at the ends of words), Anglo-Saxon poets typically used alliteration - a technique in which the first half of the line (the a-verse) is linked to the second half (the b-verse) through similarity in initial sound: 

Oft Scyld Scefing sceaðena threatum 

A line of Old English poetry usually has three words that alliterate. The meter, or rhythm, of the poetry works together with the alliteration: The stress in a line falls on the first syllables of the words that alliterate, as in the line "weo'x under wo'lcnum, weo'rðmyndum þah." (He grew under the sky, he prospered in his glory.) 

Old English poets also used kennings, poetic ways of saying simple things. For example, a poet might call the sea the "swan-road" or the "whale-road"; a king might be called a "ring-giver." There are many kennings in Beowulf, and the device is typical of much of classic poetry in Old English, which is heavily formulaic. The name Beowulf itself may be a kenning, "bee-wolf," that is, "bear." Kennings may have been traditional metaphors, and may also have allowed for improvisational composition in performance, providing phrasal synonyms that could be substituted in such a way as to complete the sense of a given line while preserving the meter. These kennings work in much the same way as epithets and verbal formulae, as prefabricated diction for modular insertion into the basic structure of the Old English line. For example, in the speech-introducing-lines: 

Beowulf maðelode bearn Ecgðeowes

(Beowulf spoke, the son of Ecgtheow)

Hrothgar maðelode helm Scyldinga

(Hrothgar spoke, the protector of the Scyldings) 

The poet has a choice of epithets or formulae to use in order to fulfill the alliteration.

Fr. Klaeber's Beowulf and the Fight at Finnsburg has been the standard Old English text/glossary used by scholars since 1908. Two recent versions with Old English glossaries include George Jack's 1997, Beowulf: A Student Edition, and Bruce Mitchell and Fred C. Robinson's 1998, Beowulf: An Edition with Relevant Shorter Texts.