Personnel: Gram Parsons (vocals, acoustic guitar); Emmylou Harris (vocals); Herb Pedersen, Bernie Leadon (acoustic guitar, electric guitar); James Burton (electric guitar); Al Perkins , Buddy Emmons (pedal steel guitar); Alan Munde (banjo); Byron Berline (mandolin, fiddle); Hal Battiste (baritone saxophone); Glen D. Hardin (piano); Steve Snyder (vibraphone); Emory Gordy (bass instrument); N.D. Smart II, Ronnie Tutt (drums); Linda Ronstadt (background vocals).

In the pursuit of what he labeled "Cosmic American Music," Gram Parsons--with the Byrds, the Flying Burrito Brothers, and as a solo artist--helped invent country-rock, forever changing the relationship between the two genres. GP, released in 1973, and GRIEVOUS ANGEL, released posthumously in 1974, are the only two studio albums on which Parsons served as the lone bandleader. With the help of Elvis Presley's backing band and a then unknown singer named Emmylou Harris on harmony vocals, Parsons wrapped up bluegrass, honky tonk, traditional country, R&B, and rock & roll in one delicious package.

Compiled here on one CD, both GP and GRIEVOUS ANGEL are packed with country-rock classics like the character sketch ballad "She," the boot-tapping "That's All It Took," and the irresistibly rocking "Big Mouth Blues," while "Return of the Grievous Angel" is an all-time Parsons gem and one of his most beautiful duets with Harris. The albums flow together perfectly, with the strength of the songwriting and musicianship guaranteeing no missteps along the way (even the covers of "Love Hurts" and a rave-up version of the Louvin Brothers' "Cash on the Barrellhead" sparkle). In addition to its status as one of the quintessential, defining documents of country-rock, GP/GRIEVOUS ANGEL is still a beautiful, satisfying listen decades after its release.