In celebration of the 50th anniversary of the first sessions for Led Zeppelin's self-titled debut, which were held this week in 1968, the band has just released three new digital-only collections. Available now are Led Zeppelin X Led Zeppelin; An Introduction To Led Zeppelin; and Rock And Roll (Sunset Sound Mix).

According to the official press release, the details on each set are:

Led Zeppelin X Led Zeppelin is a comprehensive, career-spanning 30-track collection traversing all eight of the band's landmark studio albums including definitive tracks such as "Immigrant Song," "Whole Lotta Love," "Kashmir," "Ramble On," and "Stairway To Heaven." The set also includes the "Sunset Sound Mix" of "Rock And Roll," making its digital debut here after being released for the first time earlier this year on Record Store Day as a limited edition seven-inch vinyl single, which is now the best-selling release in Record Store Day history.

An Introduction To Led Zeppelin serves as a 10-track entry point to one of the most essential catalogs in rock 'n' roll and features all the previously mentioned classic songs along with "Black Dog," "Good Times Bad Times," "Going To California," and "Over The Hills And Far Away."

Rock And Roll (Sunset Sound Mix) - The final release is the digital version of the band's first ever Record Store Day release, which was produced by Jimmy Page and previously available earlier this year as a limited edition 7-inch vinyl single. The two-track set features the digital debut of the "Olympic Studios Mix" of "Friends," a stripped down version without the orchestration of the final mix, along with the aforementioned "Rock And Roll" (Sunset Sound Mix).

Jimmy Page explained to us that when pressing the Zeppelin albums into LP records back in the day, as the process went on, sound quality was compromised the further the music got from the original tapes -- a situation that has been rectified by modern technology: "What happens is, with these albums (is) that you find that the first test pressings are pretty good, but once they get them on the production line, then the quality, sort of, it starts to disappear a bit -- or lack. With all of the advance of technology, that has sort of, preceded the point that we can. . . that I can revisit the albums and re-cut them; then it gave the opportunity to give the best possible quality at this point. And really, actually -- by hi-fi standards, this in, like reviews in hi-fi magazines -- (they say) they’re better than what the original ones were; which of course, that’s always the object of the exercise."
"Whole Lotta Love"
"Black Dog"
"Stairway To Heaven"
"Good Times Bad Times"
"Going To California"
"Ramble On"
"Kashmir"
"Over The Hills And Far Away"
"Hey Hey What Can I Do"
"D'yer Mak'er"
"When The Levee Breaks"
"All My Love"
"Babe I'm Gonna Leave You"
"Heartbreaker"
"Dazed And Confused"
"The Song Remains The Same"
"Fool In The Rain"
"The Ocean"
"What Is And What Should Never Be"
"Houses Of The Holy"
"Since I've Been Loving You"
"Misty Mountain Hop"
"Communication Breakdown"
"Thank You"
"No Quarter"
"Trampled Under Foot"
"I Can't Quit You Babe"
"In The Evening"

AUDIO: JIMMY PAGE ON QUALITY OF LED ZEPPELIN REMASTERS