For a band like The Beatles, it’s hard to nail down a specific point where everything came together. Even though Ringo Starr joining the band or the group learning to use the studio as an instrument are worthy candidates for the best moments of their career, those happened gradually rather than one moment where everything started to become legendary. As far as John Lennon was concerned, though, he felt that one particular album was where everything hit a fever pitch for them.

At the same time, it’s hard to take Lennon at his word a lot of the time, considering how much disdain he had for some of his own material. He famously thought that tunes like ‘It’s Only Love’ and ‘Hey Bulldog’ were pieces of garbage, and even though Paul McCartney helped write their classic hits with him, it had to take something truly exceptional to make him compliment his writing partner.

Right as they started to use the studio a little more on Rubber Soul, though, things had started to change. Outside of the marijuana they were smoking during their writing sessions, some of the biggest experiments that they did in the studio led to the trippiest effects in the world, like showing Western culture what a sitar sounded like or penning songs that were close to perfect like ‘In My Life’.

Rubber Soul may have prepped everyone for what was coming, but Revolver doubled down on the experimentation. Although McCartney was getting more interested in ballad-like textures, Lennon was going nutty with what he could do with his voice, practically leaving the audience wondering where the hell they were going to go once the ending of ‘Tomorrow Never Knows’ came.

Right as the summer of 1967 started, though, Sgt Pepper marked the band’s swan dive into new territory. They had finally grown out of their moptop skin, and in its place were studio technicians who were looking to do whatever it took to get the best track, whether that meant putting two takes together on the single ‘Strawberry Fields Forever’ or making surreal art like the ending of ‘A Day in the Life’ or the wonderland of ‘Being for the Benefit of Mr Kite’.

Despite his opinion that the album was a bit overhyped, Lennon couldn’t deny that Pepper marked a major turning point for the group, saying, “It was our peak, you know. And Paul and I [were] definitely working together, especially on ‘Day In The Life’… The way we wrote a lot of the time was you’d write a good bit, which was easy, and when you got stuck instead of carrying on, whenever it got hard, we’d just drop it. We’d meet each other, and I’d sing half, and he’d be inspired to write the next bit, and vice versa.”

Listening to Lennon describe the way that he and McCartney worked together, it’s hard not to see that becoming fractured at this point as well. Despite being known as the driving force behind the group, Lennon seemed to hand that duty over to McCartney on this album, letting him make his fanciful tunes the calling card of the album like ‘When I’m 64’.

Lennon may have favoured albums like The White Album for being so strange for their career, but it’s hard to deny that Sgt Peppers was a watershed moment for the group and rock and roll at large. By the time the Summer of Love fully began, this soundtrack made people believe that music could change the world.