One of the mysteries of pop and rock culture is the mercurial, even fickle nature of stardom - the Everly Brothers being a perfect case in point.

Don and Phil, both just emerging from their teens, were deservedly idolized during their 1957-1962 heyday. Their voices, ideally paired through heredity and undoubted hours of practice, gave life to a string of huge hits: "Bye Bye Love," "Wake Up Little Susie," "Bird Dog," "Cathy's Clown," "When Will I Be Loved," "Crying in the Rain."Then, poof. The brothers couldn't dent the charts to spite themselves. After mid-1962 the hits were few, far between and not particularly impactful: the ironically Beatlesque "Gone, Gone, Gone" in 1964 (Paul McCartney and John Lennon never denied their own early harmonies were indebted to the Everlys), the brightly nostalgic "Bowling Green" in the late '60s and McCartney's transcendent "On the Wings of a Nightingale" 17 years later.

For those who've followed, even sporadically, the bobbing career of the brothers Everly, Rhino's four-disc retrospective will seem a justifiable, even overdue tribute to four decades of fine musicmaking. To the curious one-time, or even newly minted, fan the collection might well prove a revelation.

Though their audience waned, the Everly Brothers continued to record together for years, until disagreement drove a decadelong wedge between them before 1983. "Heartaches & Harmonies" witnesses the quality and appeal of their musicianship - and underscores the riddle of their relative obscurity.

The collection's first volume represents their peak on Cadence Records, when most of their best songs were penned by the attuned husband-wife team of Boudleaux and Felice Bryant, from the teen angst of "Wake Up Little Susie" and the litany of "Problems" to the purity of "All I Have to Do Is Dream" and "Devoted to You." Volume 2, heralding their Warner-Reprise era, opens with 1960's "Cathy's Clown" and includes Top 10 hits like "Crying in the Rain" and the double-sided single "Ebony Eyes"/"Walk Right Back."

But then the enigma takes root. The hits ground to a halt, but wonderful music continued to pour forth. "I'm Afraid" is haunting and exquisite. "Nancy's Minuet" - a cousin to "Cathy's Clown" and James and Bobby Purify's later "I'm Your Puppet" is the product of a 1962 session that, with a harpsichord underpinning, sounds as if it was years ahead of its time.

The Everlys influenced the music of Britain's Beatles, Hollies and Peter & Gordon, and the sound ricocheted as Phil and Don absorbed and mirrored the British Invasion on songs like "Gone, Gone, Gone" and "You're My Girl." As tunes like "The Price of Love" and "Kiss Your Man Goodbye" show, they also adapted well to the mid-'60s folk-rock sound of Everly-reflective groups like Simon & Garfunkel, the Byrds, the Mamas & the Papas and Buffalo Springfield. They experimented with atmosphere, both moody and upbeat.

The final volume, chronicling the years 1968 to 1990, offers more gems, often featuring easeful folk-like harmonies: the acoustic "Empty Boxes"; the quaint underground favorite "Lord of the Manor"; Jimmie Rodgers' " `T' for Texas"; and the rolling folk-rock of "I'm on My Way Home Again"; covers of songs by James Taylor, John Denver, John Sebastian and Mark Knopfler, as well as "On the Wings of a Nightingale."

The first two hours of "Heartaches & Harmonies" comprise the most familiar songs of Don and Phil Everly, but the second two prove that, though the world hasn't been listening very attentively for 20-plus years, it probably should have been.