[Aiwendil]

Well, I've read it.

First of all, the poem (what was written of it) is, alas, rather short. I count only 853 lines total across the four finished cantos and the unfinished fifth. But there are, as one would expect from Tolkien, a few notes, outlines, and very rough scraps of verse indicating how it would have continued.

What the poem lacks in quantity it makes up for in quality. The verse is excellent; this is among the finest pieces of poetry Tolkien wrote, and I would say that his mastery of the alliterative metre here surpasses that of his other long works in that form ('The Children of Hurin' and the 'New Lays' of Sigurd and Gudrun). Particularly effective are the frequent evocations of weather and natural scenery; for example:

Originally Posted by Tolkien

In the South from sleep to swift fury
a storm was stirred, striding northward
over leagues of water loud with thunder
and roaring rain it rushed onward.
Their hoary heads hills and mountains
tossed in tumult on the towering seas.
On Benwick's beaches breakers pounding
ground gigantic grumbling boulders
with ogre anger. The air was salt
with spume and spindrift splashed to vapour.

But the real strength of the poem is in the characters that it briefly but effectively sketches. It is focused on Arthur, Gawain, Mordred, Guinevere, and Lancelot, and in a minimum of lines each of them becomes a clearly defined, well-rounded character.

Comparison with The Legend of Sigurd & Gudrun is probably inevitable. That work is undeniably the more ambitious, and the larger in scope; even if 'The Fall of Arthur' had been completed it would have been shorter and more restricted in its action. But - and perhaps precisely because of its smaller scope - 'The Fall of Arthur' feels somewhat richer and more perfectly constructed. In particular, I find the phrasing in 'Arthur' clearer and more natural than that in Tolkien's Norse poems.

As for the story, in draws chiefly from the alliterative Morte Arthure and Malory's Morte d'Arthur, following each by turns. There are, of course, points at which Tolkien departs from these sources, largely with the aims of simplifying the story or of making the plot more plausible. And particularly in the ending, as projected in his notes, he strikes his own path (though Layamon's Brut is an influence there).

The extant poem is followed by three sections of commentary by Christopher Tolkien, and as usual his commentary is exceedingly clear and cogent. The first section places the work in the context of Arthurian literature, tracing the elements of the story that come from various sources and exploring the way in which Tolkien shaped those elements for his own purposes. The second presents the notes and drafting for the unwritten portions of the poem and also looks at the very interesting but rather enigmatic connection between the poem and Tolkien's own Legendarium: the apparent identification of Avalon with Tol Eressea. The third section is a condensed but illuminating account of the evolution of the poem, and of notable changes from one draft to the next.