RICKY SKAGGS has found that a good song delivered with elegant simplicity and undeniable conviction is the key to classic country music.

For two decades country has been rooted in the traditionalism of aging honky-tonk heroes like George Jones and Merle Haggard. But Skaggs' bluegrass-based career and his unexpected commercial success are bold evidence that there is a large audience waiting to hear, in the best mountain tradition, a simple song played and sung sincerely.

Skaggs' first Epic release, "Waiting for the Sun to Shine," produced four country hits and won him a slew of awards and nominations. His latest release, "Highways and Heartaches" (Epic FE37996), is another meticulously crafted and sublime blend of traditional roots and pop instinct, of acoustic and electric instrumentation, of old-fashioned sentiment and modern romance. Intact are Skaggs' high straining tenor and imaginative guitar and mandolin stylings, all echoing back to his Kentucky childhood and his precocious affection and talent for bluegrass music.

Although Skaggs' version of Guy Clark's irresistibly bouncy and melodic "Heartbroke" is the most likely hit here, Skaggs is at his best with slow tempos and sad songs. He is one of the few country artists who trusts his music and songs enough to deliver a Carter Family-style ballad like "Don't Let Your Sweet Love Die" on the simple and affectionate terms it deserves. On two honky-tonk weepers, "Nothing Can Hurt You" and "Let's Love the Bad Times Away," Skaggs' understated phrasing is elegantly balanced by his band's exquisite fiddle and pedal-steel work.

It is the more uptempo material, however, that gives Skaggs and his sterling instrumentalists a chance to flash their musical wares. Skaggs sails into that high, almost unearthly tenor patented by Bill Monroe on Monroe's "Can't You Hear Me Crying" and picks out a stunning acoustic guitar solo. "Don't Think I'll Cry" is a western swing number that allows Buck White and Weldon Myrick to trade off blues and jazz licks, while Rodney Crowell's "One Way Rider" is given a fast, pumping country-rock treatment reminiscent of the Flying Burrito Brothers.

Throughout this album, there's a masterful sense of control and economy exercised by the band in service of the beauty of the songs Skaggs selects.

As one of the most dedicated treasurers of American folk and country heritage, Johnny Cash has always been something of a traditionalist. Although the '70s were artistically lean years for Cash, his last few albums have represented a creative resurgence, perhaps inspired by the success of young classicists like Skaggs and John Anderson, or of his own daughter and son-in-law, Roseann Cash and Rodney Crowell. In any case, Cash now records with his first-rate road band, chooses songs from the best young songwriters, and favors the spare arrangements of his original rockabilly-based sound. His latest album, "The Adventures of Johnny Cash" (Columbia FC38094), teams him with renegade producer Jack Clement, the man who worked with Cash on his first successes at Sun Records in the '50s.

Cash's sense of the past is wonderfully affirmed when he opens and closes the album's first cut, Billy Joe Shaver's "Georgia on a Fast Train," with a quavering yodel stolen straight out of Jimmy Rodgers' mouth. Similarly, Cash revives the train song legacy with rolling and thumping versions of "Ain't Gonna Hobo No More" and Merle Haggard's "Good Old American Guest." Perhaps taking a few clues from Skaggs, Cash has added mandolin and John Hartford's fiddle and banjo work to his sound, thus connecting his rockabilly roots to the mountain traditions of his inherited family, the Carters.

If this album is mostly successful, it's because Cash understands the rugged magic of his sonorous, off-key voice well enough to keep his arrangements sparse and to choose songs that dramatically resonate with his craggy pioneer image. Unfortunately, a few songs on the album fit Cash's style about as well as a Nehru jacket. The only outright mistake, though, is "We Must Believe in Magic," where Clement brings in a female chorus and string quartet to help Cash deliver some decidedly unrugged and grandiose sentiments.