From the start, the Beatles' Anthology series was going to be a three-part deal.

The first volume arrived in November 1995. Less than four months later, on March 18, 1996, Anthology 2 was released. And that's when things got interesting.

Because the series – which was the group and record company's official way of fighting bootleggers who were putting out studio leftovers and concert appearances – was arranged chronologically, the first volume chronicled the Beatles' early years with low-quality live performances, sketchy demo recordings and alternate takes of songs that were performed several times to get something worth issuing. It's an intriguing part of the band's history, but there's not much on Anthology 1 (besides maybe the outtake "Leave My Kitten Alone") that could be considered an essential missing part of the catalog.

Anthology 2 includes only three songs that were previously unreleased in any form – Ringo Starr's Help! leftover "If You've Got Trouble," Paul McCartney's "That Means a Lot" from the same sessions and the instrumental "12-Bar Original," left off of Rubber Soul at the last minute.

Instead, the Beatles' new focus in the studio revealed some significant turning points in the group's aesthetic during this fertile period.

The 45 tracks on the two-disc set span the beginning of 1965 through the beginning of 1968, and include a period where classic albums like Help!, Rubber Soul, Revolver and Sgt. Pepper's Lonely Hearts Club Band came out. It was a busy and productive era for the band, which would soon retire from playing live. All that new free time gave them plenty of opportunities to play around with songs, their arrangements and, most importantly, the way they were structured in the studio.

Watch the Beatles' 'Real Love' Video

Early takes of the Revolver freak-out "Tomorrow Never Knows" and Sgt. Pepper's "Being for the Benefit of Mr. Kite!" show the Beatles fully embracing their new playground, while a skeletal demo of "Strawberry Fields Forever" and a fuss-free "Across the Universe" uncover the songs beneath the tricks. More so than either of the other two Anthology sets (number three arrived in October 1996), the second volume includes the most widescreen collection of new shades and textures applied to some familiar old work.

Like Anthology 1, Anthology 2 included a new song assembled by the surviving three Beatles around an old John Lennon demo. And like the first collection's "Free as a Bird," "Real Love" was originally recorded by Lennon in the late '70s at his New York City Dakota apartment on cassette.

McCartney, Starr and George Harrison, along with producer Jeff Lynne (who also worked on "Free as a Bird"), recorded new instrumental passages and backing vocals to accompany Lennon's version, which was made up of just his voice and piano.

And like its predecessor, Anthology 2 debuted at No. 1. But its real legacy among Beatles fans is the bounty of previously unreleased material (most of which had ended up, in varying forms of quality, on bootlegs over the years): a live version of "Everybody's Trying to Be My Baby" from Shea Stadium, early takes of "Norwegian Wood (This Bird Has Flown)" and "Your Mother Should Know," an alternate look at 1967's relatively obscure "Only a Northern Song."

Along with the two collections that sandwich it, Anthology 2 tied up some loose ends in Beatles history, making it more than just another footnote release in their catalog.