A brief taxonomy of prolific musicians, in terms of popularity. We have the obsessed cranks, those who toil in underground music caves without the usual industry strictures to condense their output: R. Stevie Moore, Jandek, Senmuth. You’ve got your restless creatives, the major figures who earned the cultural and actual capital to indulge their every musical itch: James Brown, Frank Zappa, Prince. And you have the simply manic, the ones whose audience is larger than a WFMU Christmas party, but not large enough to send a new record careening up the charts. Bob Pollard comes to mind, and David Tibet, and the Mountain Goats’ John Darnielle.

Sasha Frere-Jones’ 2005 proclamation that Darnielle was “America’s best non-hip-hop lyricist” has gotten a lot of play in interview prefaces. (Presumably, SF-J was creating wiggle room for Nigel Blackwell and Daniel Dumile, respectively.) As the driving force behind the Mountain Goats, he’s maintained a breakneck recording pace for more than two decades; and as his band declines to take a breath, so, too have his fans. Darnielle’s a beloved indie-rock figure, someone whose considered opinions on politics, sexism, and death metal have garnered him endless Tumblr reblogs. And yet, critical consensus has yet to alight on a particular album the way it has for so many of his peers.

The band’s career can be divided into three periods: 1991 to 1995, 1996 to 2001, and 2002 to the present. The first phase was essentially solo Darnielle, with frequent contributions from bassist/singer Rachel Ware. Around 1995, other obligations kept her from touring and recording, and Darnielle began collaborating with a variety of other musicians, including Alastair Galbraith and future Goat Peter Hughes. In 2002, newly inked to 4AD, the band released its second LP of the year, and first as a full band recording in a studio. (Previous efforts were infamously laid down on personal four-tracks and cheap boomboxes.) The current lineup is John Darnielle, Peter Hughes, and drummer Jon Wurster (who also plays in Superchunk and Bob Mould’s band).

The uniformity of Darnielle’s output — nearly every song under four minutes, a singular recording approach until the 4AD years — and the conceptual framework in which he works — the “Alpha” and “Going to” series of songs, the Latin phrases that accompanied his releases for a time — make it an ideal temptation toward completism. He’s resisted the retrospective impulse, even as his songs burrow into the psyches of fresh crops of undergrads. There are no best-ofs, no expanded reissues, and just a handful of compilations gathering the harder-to-find stuff. There would certainly be some kind of market for them; on last.fm, the Mountain Goats’ songs have been scrobbled 30 million times, a shade under Pavement’s 32 million, and more than contemporary bands like Built to Spill (16 million), Yo La Tengo (24 million), and Guided By Voices (14 million).

The success of the Mountain Goats speaks to a market inefficiency in indie rock. College rock repudiated the literalism of hardcore, spawning two decades of elliptical, allusive works. The Goats weren’t the sole torchbearers of directness in the ’90s and ’00s, but they boasted a deep catalog of earnest, structurally simple works. Pick any of a hundred entry points into their songbook; I’m sure we could construct a thousand best-ofs between us. (I mentioned that no one Goats album sticks out as particularly acclaimed, but 2002’s “No Children” and 2005’s “This Year” would seem to be, far and away, the songs with the furthest reach.)

Darnielle has spoken often about his songs being short stories. Until 2004’s We Shall All Be Healed, he was keeping the personal stuff at arm’s length. (Although you can certainly argue, a la Yoko Ono, that all art is inescapably about the artist.) As for the actors within these songs: they’re a rough bunch. Most everyone is hungry for something: good news, revenge, a split. Often, they’re hungry for food. A lot of time is spent comprehending — or trying to comprehend — a lover, a friend, a mortal enemy.

That’s not to say that his ragged crew is a set of unmoved movers. The psychogeography of a Mountain Goats album is invariably as thick as a cloud of gnats. Most narrative lyricists depict a situation by getting into the narrator’s thoughts; often as not, Darnielle likes to get in through the screen door out back. Songs hinge on a scuffle in the kitchen, the sight of a peacock in the front lawn, copulation on the boggy Scottish earth.

Always, there’s a real empathy. He’s not putting his characters through their existential paces, springing cruelty or failure on them. His population typically boasts fiery wills, the certainty of their decisions, and the singlemindedness of a Captain Ahab who’s perpetually late on the mortgage. The couplet I’ve seen quoted most often belongs to Zopilote Machine’s “Going To Georgia”: “The most remarkable thing about you standing in the doorway is that it’s you / and that you’re standing in the doorway.” The narrator, of course, isn’t being dug lovestruck out of a closet; he (or she) is bearing down on Atlanta with a revolver and a maniacally beating heart.

Speaking of Atlanta, it’s worth taking a second to note the importance of location to the Mountain Goats’ output. Darnielle’s lived in a fair number of places. (Wikipedia — which currently has an article subsection called “Places Darnielle has lived” — pegs the journey as Bloomington, IN; San Luis Obispo, CA; Grinnell, IA; Tallahassee, FL; Colo, IA; Ames, IA; Chicago, IL; Portland, OR; Milpitas, CA; Denton, TX; and lastly, Durham, NC.) The sheer number of countries and cities he’s referenced could comprise an indie-rock Domesday Book, or at least a new New Traveler’s Atlas. A lot of these places are loci of suggestion, rather than immersion. “Going to Lebanon,” for instance, is typical; it gets no more specific than cedars. But the sheer accrual of landmarks across his discography has a universalizing effect, as the action plays out in a thousand varieties in a hundred towns.

As if this activity weren’t enough, Darnielle has maintained a consistent, genial online presence. Arguably, it’s contributed to his continued popularity, as the man has been continually available on the band’s message board, as well as perfectly willing to assure hundreds of indie-rock interviewers that yes, he’s genuinely into Meshuggah. His internet CV encompasses the “South Pole Dispatch” column for Decibel, contributions to the late Magnet magazine, and an incredible series of music writing on his own Last Plane to Jakarta site. Last Plane to Jakarta was the accelerant for my Mountain Goats fandom; I don’t know exactly what I expected from a boombox singer-songwriter, but it wasn’t impassioned advocacy for Cretin, Aura Noir, and late-period Geto Boys. That ecumenicalism is the biggest clue that the Mountain Goats’ corpus isn’t just a collection of impeccably imagined portraits — even though it’d be just fine if that were the case — but the work of someone led by an unslakable thirst for experience.

It’s that thirst that has seen the Goats through two decades of musicmaking. A mere three years in that span have passed without the release of new material: 1999, 2007, and 2010. Unlike a Robert Pollard, who made the transition from cassette recording to studio work with his penchant for fractured mod-pop intact, the Mountain Goats have undergone a slow evolution in sound and composition. I can’t go from flops to tops with their output; I can only indicate preferences.

What follows are descriptions of the 20 LPs in the band’s catalog, a number that includes three compilations of extended players, singles, and tracks contributed to other projects. The Mountain Goats’ consistency makes the nature of this project more than a little comical, but maybe we can look at this as a small celebration, and a quick look backwards. Register your thoughts in the comments before Darnielle releases the next five EPs.

Start the Countdown here.