"Reckoner" (Radiohead)

Admittedly, I don’t think the sun rises and sets on Radiohead.  But when Thom Yorke and the boys go off experimenting with their Theremins and throw everything from electronica to free jazz in a blender, just to see what comes out, it makes me feel all is right with the world.  So I am a fan.
Even if I weren’t a fan, I’m pretty sure I’d still love the song “Reckoner” from 2007’s near-perfect album In Rainbows, which takes its name from the backing vocal lyric sung during the bridge of "Reckoner."  
The song’s roots stretch back to early 2001, when Yorke and Radiohead’s lead guitarist/multi-instrumentalist Jonny Greenwood started working on a song called “Reckoner.”  This heavy and heavily-distorted forerunner to the final version (heard here in a 2001 bootleg recording from Washington’s Gorge Amphitheater, where the band debuted the song) was shelved for quite a few years and didn’t turn up again until the In Rainbows sessions.  As the band tinkered with the song, Greenwood and Yorke added a rhythm-driven, more introspective coda to balance out the song's hard-driving core.  In the end, the band decided they liked the new section better than the original, so they ended up tossing out everything except the coda.  
The reworked song with new lyrics became the “Reckoner” released on In Rainbows, and the abandoned song was resurrected in 2009 as the Yorke solo track, “Feeling Pulled Apart by Horses.”
Musically, the song is built around chopped-up snippets and loops of Philip Selway’s live drum track and a guitar line that, as Yorke noted on a radio interview with Britain’s XFM, was inspired by John Frusciante of the Red Hot Chili Peppers.
From various bits of commentary I’ve read about the track and the album in general, both seem to be influenced thematically by Goethe's Faust.  (The track that precedes “Reckoner” on the album is even called “Faust Arp.”)  I’ll try to give the quick, Cliff’s Notes synopsis of the drama: the plot centers around Faust, who wants to find the meaning of human existence.  So, he sells his soul to Mephistopheles, an agent of the devil, in exchange for superhuman knowledge/power/pleasure.  After years of unlimited power, Faust finally experiences a moment of pure happiness, and Mephistopheles, per their original bargain, comes for his soul.  However, Mephistopheles is thwarted by angels who whisk Faust to heaven, saving him from eternal damnation.  The end.
Considering Yorke’s struggles with sudden fame after 1993's Pablo Honey and feeling constant pressure to top his previous achievements--not to mention his gnawing concerns that he and the band were helping perpetuate crass commercialism and the rock-star myth, it seems plausible that “Reckoner” is Yorke seeing himself in a Faustian light: someone who was once handed the world on a plate (via a deal with the devil), only to realize that the true meaning of our existence is neither fame nor fortune.
The backing vocals, which repeat In rainbows...In rainbows in the song’s bridge, seem to represent finding a place of comfort and peace, outside the limelight.  (Specifically, in reflected/refracted light.)
Looking at it another way, it’s a song about mortality and coming to grips with the fact that all things must pass.
It’s heavy stuff, packaged in one of the most ethereal tracks that Radiohead’s ever done.