"Yesterday" is a song originally recorded by The Beatles for their 1965 album Help!. According to the Guinness Book of Records, "Yesterday" has the most cover versions of any song ever written. The song remains popular today with more than 3,000 recorded cover versions, the first hitting the United Kingdom top 10 three months after the release of Help!. Broadcast Music Incorporated (BMI) asserts that it was performed over seven million times in the 20th century alone. The song was not released as a single in the UK at the time of the US release, and thus never gained number 1 single status in that country. However, "Yesterday" was voted the best song of the 20th century in a 1999 BBC Radio 2 poll of music experts and listeners. In 2000, "Yesterday" was voted the #1 Pop song of all time by MTV and Rolling Stone Magazine.

"Yesterday" takes the form of a melancholic acoustic guitar ballad about a breakup. It was the first official recording by The Beatles that relied upon a performance by a single member of the band, namely, Paul McCartney. He was accompanied solely by a string quartet. The final recording differed so greatly from other works by The Beatles that the other three members of the band vetoed the release of the song as a single in the United Kingdom (however, in 1976 it was eventually issued as a single there). Although credited to "Lennon/McCartney", the song was written solely by McCartney. In 2002, McCartney asked Yoko Ono if she would consider reversing the songwriting credits on the song to read "McCartney/Lennon". Ono refused.

According to biographers of McCartney and The Beatles, McCartney composed the entire melody in a dream one night in his room at the Wimpole Street home of his then girlfriend Jane Asher and her family. Upon waking, he hurried to a piano and played the tune to avoid forgetting it.

McCartney's initial concern was that he had subconsciously plagiarised someone else's work (known as cryptomnesia). As he put it, "For about a month I went round to people in the music business and asked them whether they had ever heard it before. Eventually it became like handing something in to the police. I thought if no-one claimed it after a few weeks then I could have it."

Upon being convinced that he had not robbed anyone of his melody, McCartney began writing lyrics to suit it. As Lennon and McCartney were known to do at the time, a substitute working lyric, entitled "Scrambled Eggs", was used for the song until something more suitable was written. In his biography, Paul McCartney: Many Years from Now, McCartney recalled: "So first of all I checked this melody out, and people said to me, 'No, it's lovely, and I'm sure it's all yours.' It took me a little while to allow myself to claim it, but then like a prospector I finally staked my claim; stuck a little sign on it and said, 'Okay, it's mine!' It had no words. I used to call it 'Scrambled Eggs'."

During the shooting of Help!, a piano was placed on one of the stages where filming was being conducted and McCartney would take advantage of this opportunity to tinker with the song. Richard Lester, the director, was eventually greatly annoyed by this and lost his temper, telling McCartney to finish writing the song or he would have the piano removed. The patience of the other Beatles was also tested by McCartney's work in progress, George Harrison summing this up when he said: "Blimey, he's always talking about that song . You'd think he was Beethoven or somebody!"

McCartney originally claimed he had written "Yesterday" during The Beatles' tour of France in 1964; however, the song was not released until the summer of 1965. During the intervening time, The Beatles released two albums, Beatles for Saleand A Hard Day's Night, both of which could have included "Yesterday". Although McCartney has never elaborated his claims, a delay may have been due to a disagreement between McCartney and George Martin regarding the song's arrangement, or the opinion of the other Beatles who felt it didn't suit their image.

Lennon later indicated that the song had been around for a while before:

McCartney said the breakthrough with the lyrics came during a trip to Portugal in May 1965:

On 27 May 1965, McCartney and Asher flew to Lisbon for a holiday in Albufeira, Algarve, and he borrowed an acoustic guitar from Bruce Welch, in whose house they were staying, and completed the work on "Yesterday".

The song was offered as a demo to Chris Farlowe prior to The Beatles recording it, but he turned it down as he considered it "too soft."

Ostensibly simple, featuring only McCartney playing an Epiphone Texan steel-string acoustic guitar backed by a string quartet in one of The Beatles' first use of session musicians, Yesterdayhas two contrasting sections, differing in melody and rhythmicity, producing a sense of disjunction.

The first section ("Yesterday, all my troubles seemed so far away...") opens with a positive F-major chord, then moving to E-minor before resolving to its relative A-major and thence to D-minor. In this sense, the opening chord is a decoy; as musicologist Alan Pollack points out, the home key (F-major) has little time to establish itself before "heading towards the relative D-minor." He points out that this diversion is a compositional device commonly used by Lennon and McCartney, which he describes as "delayed gratification".

The second section ("Why she had to go I don't know...") is, according to Pollack, less musically surprising on paper than it sounds. Starting with E-minor, the harmonic progression quickly moves through the relative A-major, D-minor, and (closer to F-major) B-flat, before resolving back to F-major, and at the end of this, McCartney holds F whilst the strings descend to resolve to the home key to introduce the restatement of the first section, before a brief hummed closing phrase.

Pollack described the scoring as "truly inspired", citing it as an example of "[Lennon & McCartney's] flair for creating stylistic hybrids"; in particular, he praises the "ironic tension drawn between the schmaltzy content of what is played by the quartet and the restrained, spare nature of the medium in which it is played."

The track was recorded at Abbey Road Studios (immediately following on from taping "I'm Down") on the 14 June 1965. There are conflicting accounts of how the song was recorded, the most quoted one being that McCartney recorded the song by himself, without bothering to involve the other band members. Alternative sources, however, state that McCartney and the other Beatles tried a variety of instruments, including drums and an organ, and that George Martin later persuaded them to allow McCartney to play his Epiphone Texan steel-string acoustic guitar, later on editing-in a string quartet for backup. Regardless, none of the other band members were included in the final recording. However, the song was played with the other members of the band in concert during 1966.

McCartney performed two takes of "Yesterday" on 14 June 1965. Take 2 was deemed best and used as the master take. A string quartet was overdubbed on take 2 and that version was released. Take 1, without the string overdub, was later released on the Anthology 2compilation. On take 1, McCartney can be heard giving chord changes to George Harrison before starting, but George does not appear to actually play. Take 2 had two lines transposed from the first take: "There's a shadow hanging over me"/"I'm not half the man I used to be," though it seems clear that their order in take 2 was the correct one, because McCartney can be heard, in take 1, suppressing a laugh at his mistake.

George Martin later said:

Although McCartney had fallen in love with the song, he had a much harder time convincing the other members of the band that it was worthy of an album place, the main objection being that it did not fit in with their image, especially considering that "Yesterday" was extremely unlike other Beatles' songs at the time. This feeling was so strong that the other Beatles—Lennon, Harrison and Ringo Starr—refused to permit the release of a single in the United Kingdom. This did not prevent Matt Monro from recording the first of many cover versions of "Yesterday" to come. His version made it into the top ten in the UK charts soon after its release in the autumn of 1965.

The Beatles' influence over their U.S. record label, Capitol, was not as strong as it was over EMI's Parlophone in Britain. A single was released in the U.S., pairing "Yesterday" with "Act Naturally", a track which featured vocals by Starr. The single was charting by 29 September 1965, and topped the charts for a full month, beginning on 9 October. The song spent a remarkable total of 11 weeks in the American charts, selling a million copies within five weeks. "Yesterday" was the most-played song on American radio for eight consecutive years, its popularity refusing to abate.

"Yesterday" was the third of six number one singles in a row on the American charts, a record at the time. The singles were "I Feel Fine", "Eight Days a Week", "Ticket to Ride", "Help!", "Yesterday", and "We Can Work It Out". The record was equaled by The Bee Gees in the 1970s and surpassed by Mariah Carey in the 1990s. "Yesterday" also marked a turning point in who wrote number one singles for the group. Lennon wrote five through "Help!", whereas afterwards McCartney wrote eight starting with "Yesterday".

On 4 March 1966, "Yesterday" was released as an EP in the UK, joined by "Act Naturally" on the A-side with "You Like Me Too Much" and "It's Only Love" on the B-side. By 12 March, it had begun its run on the charts. On 26 March 1966, the EP went to number one, a position it held for two months. Later that same year, "Yesterday" was included as the title track for the U.S.-only Yesterday and Todayalbum, which was originally packaged in the "butcher sleeve".

Ten years later on 8 March 1976, "Yesterday" was released by Parlophone as a single in the UK, featuring "I Should Have Known Better" on the B-side. Entering the charts on 13 March, the single stayed there for seven weeks, but it never rose higher than number 8 (however, by this time the song had been featured on no less than three top 5 albums and an EP which topped the charts). The release came about due to the expiration of The Beatles' contract with EMI, Parlophone's parent. EMI released as many singles by The Beatles as they could on the same day, leading to 23 of them hitting the top 100 in the United Kingdom charts, including six in the top 50.

"Yesterday" has been recognised as the most recorded song in the history of popular music; its entry in the Guinness Book of Recordssuggests over 1600 different cover versions to date, by an eclectic mix of artists including The Mamas and the Papas and Barry McGuire, The Seekers, Joan Baez, Michael Bolton, Bob Dylan, Liberace, Frank Sinatra, Elvis Presley, Ray Charles, Marvin Gaye, Daffy Duck, Jan & Dean, Wet Wet Wet, Plácido Domingo, The Head Shop, Billy Dean, En Vogue, Muslim Magomayev and Boyz II Men. In 1976, David Essex did a cover version of the song for the ephemeral musical documentary All This and World War II. After Muzak switched in the 1990s to programs based on commercial recordings, Muzak's inventory grew to include about 500 "Yesterday" covers. At the 2006 Grammy Awards, McCartney performed the song live as a mash-up with Linkin Park and Jay-Z's Numb/Encore. It is Vladimir Putin's favourite Beatles song.

"Yesterday" won the Ivor Novello Award for 'Outstanding Song of 1965', and came second for 'Most Performed Work of the Year', losing out to another McCartney composition, "Michelle". The song has received its fair share of acclaim in recent times as well, ranking 13th on Rolling Stone's 2004 list The 500 Greatest Songs of All Time. In 1999, Broadcast Music Incorporated (BMI) placed "Yesterday" third on their list of songs of the 20th century most performed on American radio and television, with approximately seven million performances. "Yesterday" was surpassed only by The Association's "Never My Love" and the Righteous Brothers' "You've Lost That Loving Feeling".

"Yesterday," however, has also been criticised for being mundane and mawkish; Bob Dylan had a marked dislike for the song, stating that "If you go into the Library of Congress, you can find a lot better than that. There are millions of songs like 'Michelle' and 'Yesterday' written in Tin Pan Alley". Ironically, Dylan ultimately recorded his own version of "Yesterday" four years later, but it was never released.

Shortly before his death in 1980, Lennon explained that he thought the lyrics didn't "resolve into any sense... They're good—but if you read the whole song, it doesn't say anything; you don't know what happened. She left and he wishes it were yesterday—that much you get—but it doesn't really resolve. ... Beautiful—and I never wished I'd written it."

"Yesterday" was voted Best Song of the 20th Century in a 1999 BBC Radio poll.

The tonic key of the song is F major (although, since McCartney tuned his guitar down a whole step, he was playing the chords as if it were in G), where the song begins before veering off into the key of D minor. It is this frequent use of the minor, and the ii-V7 chord progression (Em and A7 chords in this case) leading into it, that gives the song its melancholy aura. The A7 chord is an example of a secondary dominant, specifically a V/vi chord. The G7 chord in the bridge is another secondary dominant, in this case a V/V chord, but rather than resolve it to the expected chord, as with the A7 to Dm in the verse, McCartney instead follows it with the IV chord, a Bb. This motion creates a descending chromatic line of C B Bb A to accompany the title lyric.

The string arrangement supplements the song's air of sadness, especially in the groaning cello melody and its blue seventh that connects the two halves of the bridge (on the line, "I don't know / she wouldn't say") as well as the descending line by the viola that segues the chorus back into the verses. This simple idea is so striking, McCartney mimics it with his vocal on the second pass of the chorus. This viola line and the high A sustained by the violin over the final verse are the only elements of the string arrangement attributable to McCartney rather than George Martin.

When the song was performed on The Ed Sullivan Show, it was done in the above-mentioned key of F, with McCartney as the only Beatle to perform, and the studio orchestra providing the string accompaniment. However, all of The Beatles played in a G-major version which was used in the Tokyo concerts during their 1966 tours.

When McCartney appeared on The Howard Stern Show, he stated that he owns the original lyrics to "Yesterday" written on the back of an envelope.

In 2001 Ian Hammond speculated that McCartney subconsciously based "Yesterday" on Ray Charles' version of "Georgia On My Mind," but closed his article by saying that despite the similarities "Yesterday" is a "completely original and individual [work]."

In July 2003, British musicologists stumbled upon similarities between the lyric and rhyming schemes of "Yesterday" and Nat King Cole's Answer Me, My Love(originally a German song by Gerhard Winkler and Fred Rauch called Mütterlein), leading to speculation that McCartney had been influenced by the song. McCartney's publicists denied any resemblance between "Answer Me" and "Yesterday". From the story:

In 2006, Italian producer and songwriter Lilli Greco claimed "Yesterday" to be a cover of a 19th century Neapolitan song called Piccerè Che Vene a Dicere'. In the same occasion, Greco claimed that McCartney and Lennon had an "encyclopaedic knowledge" of world music and were particularly fond of Neapolitan songs. However, following researches didn't lead to any trace of the song in the archives.

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