The experts disagree about Riders in the Sky. Do they offer "the loving re-creation and perpetuation of a myth," as country-music historian extraordinaire Bill C. Malone opines in his liner notes for the album entitled, with mythic eloquence, Always Drink upstream from the Herd? Or are they, in the words of the All Music Guide's Stephen Thomas Erlewine, a "campy western revival band"? Certainly the pervasive humor of the Riders' self-presentation argues for the latter position. "Past performance is no guarantee of future results," warns the list of credits on one CD. In their hand, "The Legend of Paladin" (theme of the TV western Have Gun, Will Travel) becomes "The Legend of Palindrome," featuring a cowboy who can speak only in sentences that read the same backwards and forwards.

But the jokes mostly stop when the music begins; even if the Riders' covers of the classics of Hollywood cowboydom aren't exactly straight-ahead, they're always delivered with a smile rather than a smirk. It's done, as Malone says, with love. The Riders are too left-field, too college-town in their outlook ("Ranger Doug" Green lived in Ann Arbor for years) to be called revivalists, exactly, but your impulse after seeing their show is to buy a collection of old cowboy songs rather than to laugh the whole thing off.

Riders in the Sky have been compared to Garrison Keillor for their ability to draw creative sustenance from a sentimentalized past at the same time as they are sending it up. They've often appeared on Keillor's Prairie Home Companion, and they've been around nearly as long as he has: the first Riders album, Three on the Trail, came out in 1979. How have they done it? The answer to that question might be as multifaceted as it would be for Keillor, but there are a few things that stand out.

One is the group's often overlooked musicianship, based on a grasp of how the best western music was always underpinned by jazz. Few musicians on either the jazz or the country side of the ledger can touch fiddler Woody Paul on a swing fiddle solo like "Cherokee," and bassist Too Slim and occasional accordionist Joey the Cowpolka King realize that dance rhythms are important even when nobody's dancing. The fiddle-and-guitar interaction of Paul and Green puts western music aficionados in mind of Hugh and Karl Farr, the Texas brother duo who put the zing in the music of the greatest of the 1930s cowboy acts (and the one in which Roy Rogers got his start), the Sons of the Pioneers.

The Sons of the Pioneers inspired Riders in the Sky in other ways as well — in their close trio harmonies and amazing trio yodels, for example. Most important of all was how Sons of the Pioneers songwriters Bob Nolan (who was Canadian) and Tim Spencer looked for sheer poetry in cowboy imagery. You'll hear subjective, reflective Sons of the Pioneers songs like "Tumbling Tumbleweeds" and "Cool Water" at a Riders in the Sky concert, and Ranger Doug's many originals have a poetic cast grounded in both a measure of reverential myth-remaking and a bit of distance.

Riders in the Sky visit the Ark on Sunday, October 20. A big crowd for this semihometown act is probable, so don't delay on those tickets.