In other words: At what point did the transition from their early to their later work occur?

I always considered the first of their late albums to be Sgt. Peppers, but many consider the transition to have occured earlier than that.

BTW, I'm going by the UK albums, not the US releases.

I think it's earlier than Sgt.Peppers, Rubber Soul is the one where things began to change drastically.However, it is Sgt.Peppers which revolutionised everything!

I've picked Sgt. Pepper's because it was the album where they stopped touring. So I kind of see it as the beginning of the 2nd half of their career. Also, it was their most drastic change to date. But you could say that the beginnings of their musical changes are shown in Revolver and Rubber Soul also.

ehh i really agree with followsun but i picked revolver because this was when all the songs that george wrote, like the indian culture songs came in and it was the time period where they all started getting pretty heavy on drugs, and it was really the start of the "weird" period for them. BUT! i love this album and all the rest after it. haha.

This album was definitely a transition for them. Actually, I think Help! was the first album where they showed sings of real musical advancement.

The "later" era to me is when they started growing facial hair.

Revolver is where things went psychedelic.

Sgt.Pepper, because they all ('cept Paulie!) grew facial hair then.

actually the single paperback writer/rain started it but that was in between rubber soul and revolver unlike George's opinion rubber soul and revolver for me are two different albums rubber soul was a folk album and revolver was an experimental album revolver was the 1st album to do lots of things more than rubber soul and sgt pepper combined it was the 1st album with swearing [heard in love you to] it was the 1st with reverse effects 1st time a song in general did that was in rain while rubber soul experimented more with lyrics and electric piano's revolver used reverse effects tape loops and it was the 1st album to use vocal effects besides double tracking like flanger and converting vocal chords through a LESSLE SPEAKER 1 more thing listen to the beatles in mono

with rubber soul the band was clearly moving in a new direction but they still went with the love song formula but this time on rubber soul love songs were more about affairs and possible divorce but with revolver there were more new subjects (LSD)

I got each album as they came out and followed a sort of natural transition as they became more evolved.
BUT.....Sgt.Pepper was a shocker !

As soon as they grew facial hair, I think it was the start of the later years. And they'd been putting less and less love songs on their last two albums, but now we know it wasn't just an oversight, they're never going back... I've got to stop, I'm depressing myself.