The Beatles found another deft balance between the two dominant traits of songwriters John Lennon and Paul McCartney on "Getting Better" – but only after Lennon had swum through a particularly disorienting experience with LSD.

Ensconced at Abbey Road Studios during evening sessions for Sgt. Pepper’s Lonely Hearts Club Band in March 1967, Lennon suddenly couldn't finish the vocal take. "I thought I was taking some uppers and I was not in the state of handling it," he later told Rolling Stone. "I took it and I suddenly got so scared on the mic. I said, 'What is it? I feel ill.' I said I must go and get some air. They all took me upstairs on the roof, and [producer] George Martin was looking at me funny, and then it dawned on me that I must have taken some acid."

Martin only discovered what had happened with Lennon much later. "John was in the habit of taking pills – uppers – to give him the energy to get through the night," Martin said in All You Need Is Ears. "That evening, he had taken the wrong pill by mistake – a very large dose of LSD. I knew they smoked pot, and I knew they took pills, but in my innocence I had no idea they were also into LSD."

Martin may not have known he was Lennon was tripping, but they would have headed upstairs at Abbey Road either way. "I couldn't take him out the front because there were 500 screaming kids who'd have torn him apart," Martin said in an interview for the Anthology project. "So, the only place I could take him to get fresh air was the roof. It was a wonderful starry night, and John went to the edge, which was a parapet about 18 inches high, and looked up at the stars and said, 'Aren't they fantastic?' Of course, to him I suppose they would have been especially fantastic. At the time, they just looked like stars to me."

McCartney and George Harrison continued recording the background vocals for "Getting Better," which was finished two days later with the addition of congas by Ringo Starr. These new pieces were placed on top of a basic track dating back to March 9, when the Beatles began seven early takes. Martin produced an unusual piano sound by directly striking the instrument's strings, while Harrison added a tambura drone on March 10.

Interestingly, the song's title didn't spring from the rich imaginations of either Lennon or McCartney, but instead a one-time former fill-in member of the band. "It's getting better" was a favorite saying of Jimmie Nicol, who subbed for an ailing Starr over eight days during the Beatles' 1964 world tour before disappearing back into anonymity. The phrase reportedly popped into McCartney's head while walking his sheepdog one day in 1967.

In keeping, "Getting Better" began life as an appropriately upbeat song, reflecting both the chirpy title and McCartney's general disposition. "I often try and get on to optimistic subjects in an effort to cheer myself up and also, realizing that other people are going to hear this, to cheer them up too – and this was one of those," McCartney told Barry Miles in Many Years From Now.

Then Lennon joined in the creative process. "I’m writing, 'It's getting better all the time' and John comes in with, 'Couldn’t get no worse,'" McCartney told the Washington Post. "Instead of going, 'Oh, you're spoiling my lovely song.' I go, 'Genius, great.' I would do the same thing for him."

Lennon also later took ownership of surprisingly dark lyrics lamenting youthful violence toward women, something that created a striking narrative contrast for the song – even as it coincided with his own personal awakening.

"It is a diary form of writing," Lennon told David Scheff in All We Are Saying. "All that 'I used to be cruel to my woman, I beat her and kept her apart from the things that she loved' was me. I couldn't express myself and I hit. I fought men and I hit women. That is why I am always on about peace, you see. I am a violent man who has learned not to be violent and regrets his violence."

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