The manuscript is in the British Library, and normally on display to the public under a glass case. It is traditionally known as Cotton Vitellius A. XV, because it came to the British Museum (which until recently included the Library) from the collection of the antiquary Sir Robert Cotton (d. 1631), who arranged his books under busts of Roman emperors: of Vitellius, in this case.

Before that it may have been in the possession of Laurence Nowell (d. 1576), the Dean of Lichfield and a pioneer in Anglo-Saxon studies; before that, presumably preserved in a monastery. In 1705 it was catalogued by Humphrey Wanley, who briefly quoted passages from it.

These are of interest because in 1731 the Cotton collection, then housed in Little Deans Yard in Westminster, was devastated by a fire. Vitellius A. XV, the only manuscript of any part of Beowulf that has ever been discovered, survived the fire with only its edges damaged, but the edges have been crumbling away ever since, and a considerable amount can no longer be recovered.

We are dependent at crucial points on the first publication, completed in 1787 and printed in 1815, by Grímur Thorkelin, an Icelander. He made a copy himself, now called Thorkelin B, and employed a professional copyist to make an independent copy, Thorkelin A. As the copyist had no knowledge of Old English, his is in some ways more objective, since Thorkelin (and every scholar since who has ever worked on it) was prone to finding scribal errors to allow the text to make more sense.

Some text has been recovered by modern techniques such as ultraviolet inspection.

Two scribes wrote it down, one up to line 1939 and the other to the end (line 3182). The second scribe also wrote Judith, bound after it in the same book. They were both writing in the classical Wessex dialect, but differentially preserve older forms from other regions, allowing scholars to guess at the tale's history. The text is divided into forty-three fitts.

It seems fitting to end by giving an example of the Old English. These are the last lines of Beowulf.
þá ymbe hlæw riodan hilde-déore,
æþelinga bearn, ealra twelfe,
woldon ceare cwíðan, kyning mænan,
word-gyd wrecan ond ymb wer sprecan:
eahtodan eorlscipe ond his ellen-weorc;
duguðum démdon, swá hit gedéfe bið
þæt mon his wine-dryhten wordum herge,
ferhðum fréoge, þonne hé forð scile
of líc-haman læded weorðan.
Swá begnornodon Géata léode
hláfordes hryre, heorð-genéatas;
cwædon þæt hé wære wyruld-cyninga,
manna mildust ond mon-ðwærust,
léodum líðost ond lof-geornost.

Then round the barrow rode the battle-bold,
princes' children, all twelve,
wanted to tell their sorrow, talk of their king,
utter their elegy and speak about the man:
esteemed his earlship and his works of valour;
it seemed to his followers, that it be fitting
that a man praise with words his friend and lord,
love his spirit when he should go forth
led from the body-husk.
So lamented the Geat people
their lord's passing, the hearth-retainers;
said that he was, of the world's kings,
mildest of men and gentlest
kindest of people and keenest for praise.