Union is worth it alone for the transcendent guitar-duet instrumental arrangement of "Wildwood Flower," otherwise a piece that long ago passed into the realms of insomnia cure. Once upon a time I told myself I could abide it any longer only in Woody Guthrie & the Almanac Singers' "The Sinking of the Reuben James." Florida guitarists Sam Pacetti & Gabriel Valla, however, remind us there is nothing wrong with a tune that is in truth well worth staying awake for. (It started life as the melody of the wordy 1860s parlor ballad "I Will Twine 'Mid the Ringlets," the lyrics to which the Carter Family later mangled into incoherence in the version they recorded under the present title.) It just needed somebody with the creative vision and technical chops to do it right.

With two acoustic guitarists -- with backgrounds in flamenco, classical, folk and bluegrass between them -- as formidable as Pacetti & Valla, you'd expect a bunch of instrumentals. Were that proven to be the case, complaint would be out of the question. (Their two guitars comprise the entirety of the albums' instrumental accompaniment.) As it happens, though, the two are possessed of clear, affecting singing voices they employ to powerful, if tasteful and restrained, effect on each of the nine songs here. Three are Pacetti originals, high-toned but pretension-free art-folk compositions, the most immediately arresting of which is the rolling and hypnotic "Augustine." Pacetti's writing and singing remind me of the work of my longtime friend Eric Peltoniemi, who now heads the Red House label and remains one of the finest unheard songwriters in America. To me, that's big praise.

Another highlight is Leslie Smith's "Dark Horses," set to the sort of silkily flawless melody I ordinarily associate with Gordon Lightfoot, its lyrics laying down an extended metaphor based more or less on the biblical injunction that "the last shall be first." With the sole exception of Lucinda Williams (whose reading appears on the 2001 Vanguard tribute Avalon Blues as "Angels Laid Him Away"), nearly everybody's version of Mississippi John Hurt's murder ballad "Louis Collins" sounds as close to the original as imaginative failure renders possible. Pacetti & Valla, on the other hand, approach it afresh, not with the agonized, horror-stricken interpretation Williams (brilliantly) affords it, but with the strangely mellow arrangement with which Hurt sang and picked it, only with what is mostly a new melody. (Hurt's melody, incidentally, was borrowed from the African-American folksong "Railroad Bill.")

"Ft. Worth Blues," a lament for the passing of Townes Van Zandt (who is never mentioned by name), is among my favorite Steve Earle songs. The original (on Earle's 1997 El Corazon) is suffused with melancholy. If Pacetti & Valla's is hardly a radical revision, it captures the original's nuances and if anything adds a layer of sadness.

Recordings like Union are scarce in an era when rural rusticity on one side and urban singer-songwritery on the other represent the norm in acoustic music. With its tradition-informed but distinctive, richly melodic approach untainted by anything that smacks of the expected or the cliched, an album like this is to be treasured. To be honest, the first time I put this disc on the player, I entertained minimal expectations. It's good to be reminded once in a while that all of life's surprises are not unpleasant ones.