Steve Earle calls Buddy Miller's 1995 debut Your Love and Other Lies the country record of the decade, and I believe him. Yet it wasn't until I heard Miller's new album, Poison Love -- and specifically, his cover of Otis Redding's 1965 hit "That's How Strong My Love Is" -- that I finally put my finger on what made his debut so monumental: Miller approaches country as soul music. It's not that his records are bereft of fiddle-and-steel honky-tonk (hardly), or that they adapt soul conventions to the country idiom. (Miller, in fact, does just the opposite on the aforementioned Stax-Volt classic, substituting keening pedal steel for the stately grandeur of the Memphis Horns.) Rather, it's Miller's attention to groove -- be it the rhythmic undertow of "Don't Tell Me" or the roadhouse swagger of "Help Wanted" -- that lends his music its soulful feeling. Miller's approach to country music isn't unprecedented: From the driving blues of Bob Wills & His Texas Playboys, to the hillbilly boogie of Moon Mullican, country performers often have drawn on R&B antecedents. The reverse, of course, has also been the case -- evident in the country recordings of Ray Charles and Ivory Joe Hunter, to list but two examples. Perhaps the most fertile cross-pollination of these musical sensibilities, though, took place at Syd Nathan's King Records during the 1940s and '50s. Not only was King where Henry Glover -- a veteran of the jazz orchestras of Lucky Millinder and Buddy Johnson -- produced jump blues singer Wynonie Harris, as well as hillbilly artists Hawkshaw Hawkins and the Delmore Brothers; it was once home to both James Brown and the Stanley Brothers. The easy mix of country and R&B influences that flourished at King, especially the close harmony singing and urgent rhythms of the Delmore Brothers, is arguably the hallmark of Buddy Miller's music. His back-alley duets with Lucinda Williams and Dan Penn on Your Love and Other Lies certainly suggest as much, as does the heart-rending version of the Louvin Brothers hit "You're Running Wild" Miller sings with his wife, Julie. Down-home influences are equally abundant on Miller's new album, particularly on a handful of vocal collaborations. Jim Lauderdale joins him on "Nothing Can Stop Me", a "River Deep, Mountain High"-style profession of love penned by George Jones and Roger Miller. Steve Earle chimes in on the rumba-driven "Poison Love", a 1951 hit for Johnnie & Jack written by Mr. Elmer Laird. Emmylou Harris, with whom Miller has been playing guitar for the past couple years, sings along on a tortured version of Julie Miller's "I Can't Help It", the verses of which bear striking rhythmic and harmonic resemblances to Smokey Robinson & the Miracles' "What's So Good About Goodbye". Much of Poison Love burns with a dark passion that gives the lie to Miller's affable sideman/guy-next-door demeanor. It's there in his fondness for brooding, Appalachian-style ballads such as "Baby Don't Let Me Down" and "Draggin' the River". And it's altogether palpable on "Don't Tell Me", a love song of cosmic proportions that finds Miller's vocals evoking those of legendary soul singer James Carr, perhaps best-known for his late-'60s recordings of "The Dark End of the Street" and "Pouring Water (On a Drowning Man)". Miller enlisted two ensembles for the Poison Love sessions, one featuring Emmylou Harris' touring band (including Harris on guitar), the second including longtime Miller cohorts Gurf Morlix and Donald Lindley on bass and drums, respectively. Sam Bush (fiddle), Tammy Rogers (fiddle, mandolin) and Steve Fishell (steel guitar) appear with both units, while Miller's heat-seeking guitar work -- equally masterful in blues and honky-tonk settings -- anchors the proceedings. Ultimately, however, it's the rapport among the musicians, most of them not just colleagues but also close friends, that gives the record its fiery grit. Only occasionally -- as on "100 Million Little Bombs" and "Love Grows Wild" -- does their playing fail to generate enough of a spark to ignite Miller's consistently first-rate material. Is Miller's new record as undeniable as his debut? Probably not, but that only means Poison Love is a four-star effort compared with Your Love and Other Lies, an album that rates an unqualified five. Perhaps the bigger question, especially in view of Miller's transcendent collaborations with other performers, is whether it makes sense for Buddy and Julie -- a prodigiously gifted couple who already write and sing together -- to pursue their musical vision as a duo, the '90s equivalent, say, of a non-combative Richard & Linda Thompson. As it stands, Miller's two albums for HighTone, along with his work on his wife's incandescent Blue Pony and his fevered contributions to the sessions that might eventually become Lucinda Williams' next album, prove him to be an artist of uncommon feeling and depth. Not only has Miller internalized the rhythmic first principle of soul music -- and of all down-home music, be it blues, gospel, honky-tonk or R&B -- he's also emerging as the most groove-oriented country performer working today.