Sgt. Pepper is the most influential album in the history of popular music.

Regardless of album sales or Wikipedia's opinion, Sgt. Pepper is still more influential than The White Album and Thriller. Although Sgt. Pepper may not sound innovative today, in 1967 it was the first of it's kind. In an attempt to recreate the psychedelic experience, The Beatles experimented with every aspect of their music, and created elaborate productions that questioned how much time and effort should be put into a song and album. What normally took bands a few weeks to write a record took The Beatles nearly six months. The arrangements of every song were extremely complex, containing a wide variety of instruments and effects that were a wakeup call to the industry and the artists within it. They were declaring themselves artists, and vinyl was their canvas. The White Album, however, was hardly as influential as Sgt. Pepper. It had it's share of catchy songs, like every Beatles album, but it was really nothing more than a deliberate attempt to move away from the production values they embraced during the recording of Sgt. Pepper. I fail to see how something with such a lack of innovation could possibly influence artists or the record industry. The songs were nothing special, and it probably contains more half-hearted attempts at songwriting than any other Beatles album. I also find it ironic you cite 'Ob-la-di, Ob-la-da' and 'Back in the U.S.S.R' as influential songs. Paul McCartney wrote 'Ob-la-di, Ob-la-da' as a direct homage to the Reggae movement that was emerging at the time, proving he was actually influenced by other music when writing it. He also wrote 'Back in the U.S.S.R' which although catchy, was mainly a collection of parodies poking fun at The Beach Boys, 'Georgia's On My Mind' and Chuck Berry's 'Back in the U.S.A'. I'm sure they were popular songs in 1968, but they're no more popular than 'Help!', 'Eleanor Rigby', or 'We Can Work It Out'. I also believe the reason The White Album sold so many copies is because it directly followed Sgt. Pepper. I will now further prove my opening statement. Sgt. Pepper's impact on the course of music is perhaps its greatest achievement. It was the official start of psychedelic rock. After Sgt. Pepper, more and more artists attempted to push the boundaries of music for the sake of LSD, and they frequently looked towards Sgt. Pepper for inspiration. LSD was the perfect excuse to experiment and be creative, and when combined with the fierce competition between bands, music was rapidly evolving into high art. It was this battle between bands to make the better psychedelic album that led to Progressive Rock, a hugely popular genre that would peak soon after Sgt. Pepper in the mid-70's. Progressive Rock, or Art Rock, is rock music that pushes the technical and compositional boundaries of music. Prog Rock bands purposefully experiment with song structure, texture, and rhythm, and incorporates the latest technologies while doing so. It's basically viewing music artistically. It's very similar psychedelic rock, but the bands experiment for artistic purposes, as opposed to recreating the psychedelic experience. Prog bands were hugely popular until 1974, when the four biggest prog bands, Yes, Emerson Lake and Palmer, Genesis and King Crimson went on an indefinite hiatus. In essence, without Sgt. Pepper's enormous success, psychedelic rock would not have been as popular as it was in the late 60's, and thus progressive rock would not have been as popular. Bands such as Yes may have never existed. Sgt. Pepper's artistic and mainstream appeal opened the minds of a wide range of people, allowing them to realize there's more to music than guitars and drums, and verse and chorus. It helped create an artistic mindset towards music, and changed music forever.