One a straight -ahead career overview, the other an almost insanely generous overhaul of rarities and lost cuts spread across four crammed discs, two parallel histories of the band's journey from no-nonsense country-rockers to esteemed elder statesmen of American alt/art rock are on offer here. There's the 'official' story told via chosen cuts from the band's studio albums on What's Your 20?. For the converts, Alpha Mike Foxtrot's alternative account will be of keen interest, even if no unreleased tracks are included. To demonstrate Wilco's strike rate, this treasure trove of covers, B-sides, limited editions, soundtrack cuts (fun Wilco fact: the band contributed a song, Alpha Mike Foxtrot's infectious "Just A Kid", for the Spongebob Squarepants movie), demos and copious live takes would work almost as well as a point of entry for a Wilco novice as the 'greatest hits'.

One of the first cuts on the rarities comp Alpha Mike Foxtrot, "Somebody Else's Song" (a 1994 demo of a tune later included on 1996's Americana landmark Being There) provides a handy point of entry to the band's ongoing saga. A downbeat lamentation regarding the difficulty of writing a song that doesn't instantly bring to mind a better-known number, possibly a coded reference to the creative tensions that led to Wilco chief, sonwriter and singer/guitarist Jeff Tweedy's exit from alt. country pioneers Uncle Tupelo, the scratchy cut provides a reminder that in the beginning, Wilco weren't all that original or seemingly ambitious. Tracks drawn from or around 1995 debut AM are unremarkable country-rock fare; for all their charms, there's little amidst the bar-room brawl and spilt beer of, say, "I Must Be High" to suggest the band would warrant the kind of celebrations we're now discussing 20 years later.

Fast-forward to 1996's epic double Being There. Wilco are still operating firmly within the great American music tradition, but the vision is grander, the ambition keener and the way the reference points are mixed, matched and messed around with much, much more compelling; simply, Being There - possibly a concept album regarding a struggling band operating on the edge of abyss, maybe not that of much a work of fiction for Wilco at the time - must rank amongst the very finest totems of contemporary Americana, and it's fittingly prominent on both comps. Suitably worn-out and weary live takes on "Sunken Treasure" and "Red Eyed and Blue" on Alpha Mike Foxtrot are especially noteworthy. Lack of "Far, Far Away", "Say You Miss Me", "Hotel Arizona" or the incomparably lovely, deep-blue "The Lonely 1" on What's Your 20? is obviously some sort of an oversight; the latter is included on Alpha Mike Foxtrot as a street noise-infested alternate take that seems to point towards more experimental things to come. This is where Tweedy truly found his feet as a songwriter, mixing blue but unbeaten melancholy and shook-up and shaken storytelling to a sense of the release verbalised in the best of the rock 'n' roll canon, the wealth of it, from arcane roadhouse honky tonkin' to battered blues lamentations and various highpoints (Television, The Velvet Underground, Neil Young) of the great and the good in a music obsessive’s universe, reflected in the band's expansive, versatile sound. Wilco may be most fondly regarded for their weepers, but they've always known how to kick up a cloud of sawdust, too. Wilco's mastery of American roots music styles is further reflected in the Mermaid Avenue project where the band, alongside Billy Bragg, was invited to provide music for unpublished Woody Guthrie lyrics. Released in two halves in 1998 and 2000 and well-represented on both comps, these albums set the template for similar reimagining projects to follow.

Three years on, and there's not a pedal steel or wheezing harmonica in sight. Sandwiched between its masterful predecessor and the noble reinvention that was to follow, the sleek but barbed power pop classicisms of 1999's Summer Teeth can get overlooked. Unfairly so: a frantic live take on 'Can't Stand It' and a spooky demo take on the haunting and haunted "Via Chicago" - an obvious precursor for the fraught emissions of Yankee Hotel Foxtrot, with Tweedy half-whispering the song's disorientating account of dislocation and relationship turmoil -  provide some of the greatest thrills of Alpha Mike Foxtrot, and the studio cuts from this era on What's Your 20? provide a reminder of the huge contribution that the late multi-instrumentalist (and Tweedy's occasional co-writer) Jay Bennett made to Wilco's gradual shift from sour-breathed earthiness to more experimental, sophisticated and unsettled sounds. 



Having discovered and perfected a hitherto underutilised skill for pop hooks, most bands would've gone for more of the same in the hope that if they keep writing earworms the calibre of "A Shot In The Arm" or "I'm Always in Love" (on What's Your 20?), the elusive hits will eventually follow. Wilco had other ideas. As well as carrying huge tunes such as "Heavy Metal Drummer" and especially the indelible "Jesus Etc.", Yankee Hotel Foxtrot presented a more fractured, fraught and tense sound, with songs such as the hypnotic "I Am Trying to Break Your Heart" rejecting verse/chorus conventions in favour of more disjointed structures, the drone-y detours and radio static perfectly reflecting the acute sense of unease and impending sense of doom of the lyrics. Prominently featured on What's Your 20?, these tracks still sound like a landmark reimagining of a band's musical parameters without losing sight of what made them stand out in the first place. At the time, such open-eared explorations led to no end of trouble, with Tweedy and Bennett's relationship damaged beyond repair and Wilco's label Reprise dropping the band for making such an uncommercial record; ironically, the band were soon snapped up by another Warner subsidiary and, once it was finally released in 2002, Yankee Hotel Foxtrot became Wilco's most commercially successful record.

Yankee Hotel Foxtrot is probably the one widely recognised classic in the Wilco catalogue. A Ghost Is Born (2004) is just as strong. If Yankee Hotel Foxtrot was the sound of a band disintegrating and facing active resistance whilst trying to map out new routes in unfamiliar territory, Wilco sound more assured and willing and able to flex their muscles on the follow-up. The album’s steely, harsh, jagged but also starkly beautiful sound is the work of a band who know they've arrived at the correct destination, with the white-knuckle tension and malignant moods of "Handshake Drugs" battling it out with the uncluttered beauty of "Hummingbird" and the caffeinated roar of "I'm A Wheel". Perhaps tellingly, this era is the source of the meatiest outtakes on Alpha Mike Foxtrot: the nylon-stringed, ghostly reveries of "More Like The Moon" must have been lost under the couch in the studio, otherwise its non-inclusion on the album is borderline impossible to comprehend; the raw and ragged "Let Me Come Home" and Yankee Hotel Foxtrot reject "Cars Can't Go" are equally impressive.

Having effectively fallen apart, Wilco gradually regrouped as one of the most formidable live acts around with a steady six-piece line-up (solid to this day) featuring the talents of avant-guitar whizz Nels Cline and multi-instrumentalist Pat Sansome. Consequently, Wilco's music has settled into a more comfortable groove, anchored by an own studio, even an own label to keep various music biz wolves at bay. However, there's not that much out-there intent in latter-day Wilco albums (their improvisation-friendly, high-octane live shows are a completely different matter) to upset any bottom line-obsessed label head. The domestic drama of "Hate It Here" (featured across the two comps in both studio and live versions), whilst appealing and impeccably performed, can't quite compete with, say, the explosive tension and raw nerve-endings that fire up a 2004 live take of "At Least That's What You've Said", a stunning example of how to milk the fretboard without slipping into needless histrionics. Wilco could still hit the bull's eye even when operating amidst the tasteful confines of the soft-rocking Sky Blue Sky (2007) and the poppy Wilco (The Album) from 2009: check out the duelling guitars of "Impossible Germany", especially in its live incarnation of Alpha Mike Foxtrot.

Disappointingly, the two cuts from most recent album The Whole Love (2012) which suggested a return to active risk-taking - "The Art of Almost", "One Sunday Morning" - are nowhere to be seen; they would have provided a compelling exit point to either compilation. To paraphrase an absent Being There gem, who knows what the world's got in store for Wilco next, but the fact that Tweedy's recent solo/duo album Sukierae (with son Spencer on drums) presents a return to the fractured moods and emotional rawness that fired up the band's best works bodes well for the band's future. These two comps, then, offer a reflection on the band's past achievements and the clearing of the rarities cupboards: cut out a handful of one-laugh oddities tossed aside with punky abandon, and Alpha Mike Foxtrot beats most bands official catalogue. Fittingly, the rarities comp signs off with a good-humoured take on Nick Lowe's "I Love My Label", the band still keeping their ears to the ground for fresh inspiration but only sounding like anyone when they choose to do so.