There's a page I started for Holly after we saw "Across the Universe" here, with notes and links.
I don't love the album Yellow Submarine, meaning it's not in my top fifty or anything, but I think if you listen to it a couple of times and try to ignore the story and the lyrics, and listen to the drums... and then another time, same thing, listen to the bass, it will be a good example of how rich even the less stellar of their songs are.
It was a big deal, then, to do a full-length animated movie, and to do one pretty much in a psychedelic style, seemingly based on Peter Max-style art, was the iceberg of which the Yellow Submarine song itself is only the tiniest tip.
"Hey Bulldog" is short, good, and obscure. It's on the Yellow Submarine album, but wasn't in the movie. The first section is like a duet between the bass guitar and the voice, and then George Harrison comes in with lead guitar after that.
"Within You Without You" was during the Hinduism phase, and uses sitar, tabla and Indian rhythms. As to English, the title and tagline is ambiguous. "Without you" can mean both "outside of you" and "in your absence." So that's cool. Hinduism holds reincarnation to be the constant, and so even between lives, one is still part of the greater life.
Wikipedia's Beatles page with a good summary and links galore. There are stories there I'd never heard of (and I used to read everything I could find). Something rough and interesting about Imelda Marcos and the Phillipines in 1966!