Just found this 'study' on Rain and Paperback Writer. A long shot, but some interesting points of view.
General Points of Interest
Style and Form
For all of its musical and technical innovation, it's a bit ironic to note how standard is the form and harmonic content of this song.
Though no sitars or other ethnic "world music" instruments are used here, the style of the song very much connotes the style of classical Indian music by virtue of the droning harmony and the, at times florid tune.
Melody and Harmony
As far back as "Love Me Do" (amazingly), John and Paul had stumbled onto a novel use of spicy little trills and languorously stretched out melismas that, along with sung open and parallel fifths, is truly one of the more subtle trademarks of their early "sound". Here, what is essentially the identical technique is pushed beyond the routine envelope to create an entirely new and exotically "foreign" effect.
Aside from ornamentation, the tune is structurally organized in a very "Indian" manner; with the approximate two halves of the melodic octave each isolated to its own respective section of the song; the verse stays carefully within low G up to E, while the refrain deals with the upper end of the octave, from the high G down to middle C.
The harmonic budget is frugal to the extreme of creating, what I can only assume is, an intentionally static effect. You'd expect the use of I -» IV -» V throughout this song to create a much more non-modally inflected sense of G Major as the home key than was the case in "Paperback Writer". It's intriguing, though, to contemplate how the even more widespread use in "Rain" of superimposed chords and the ornamentalized melody manage to over-ride the sense of clear Major mode and suggest something Modally tangy in flavor, even though the "letter" of the musical text does not support this notion!
Arrangement
Both vocal and instrumental tracks on this song were subjected to speed changes in between original recording and mixdown for mastering, and this detail accounts for, as much as any other factor, the psychedelic, surreal quality that surrounds the whole of it.
Lewisohn (ibid.) tells us that the backing track was performed in fast tempo (and, implicitly, in a higher key than G), so that it could be slowed down on playback to what we have on the final recording; thus altering not only the pitch but the 'textural' sound of the ensemble. The vocals (at least John's lead) were manipulated in the opposite direction (though Lewisohn inadvertently tries to confuse us on this point); in other words, John sang for the recording in a slower tempo and lower key, so that on faster playback his "Mickey Mouse" vocal not only presents him uncharacteristically beyond his normal upper range, but also with an eerily hyperactive vibrato in his throat.
John's double-tracked lead vocal is accompanied by George and Paul in the verses, and by John Himself in the refrains. The backers starts in the second verse, where they either echo and comment on what the lead sings or else they "emboss" what he sings by harmonizing right along with him.
Ringo has a veritable field day on the drums and cymbals throughout. Also, even on this relatively "progressive" track, they take the time to bother with one of their so typically fussy tambourine parts; on all four beats in the intro, on alternate even-numbered beats in the first pair of verses and the refrains, and shaken on every eighth note of the measure in verses three and four.
5 Section-by-Section Walkthrough
Intro
We have here as attention-grabbing an opening in its own way as is the "a capella" vocal opening of "Paperback Writer"; a ra-ta-tat half-measure's fanfare of solo snare drums, followed by four measures of the drone-like guitar vamping on the I chord (equally reminiscent of both tamboura and pipes) that pervades the piece.
The lower reaches of the arrangement definitely sounds as though there are some kind of open fifths at play; whether they are sounded entirely by the bass guitar, or are a composite of bass and lead guitar is not easy to ascertain given the level of distortion applied to the finished track.
Verse
The verse is an asymmetrically phrased nine measures in length; parsed as 5 (actually 3 + 2) + 4:
|G |C D |G |
G: I IV V I
|C D |G |
IV V I
|C |- |G |- |
IV I
[Figure 91.3]
Uneven phrase lengths are another good example of an off-beat compositional technique that had been a manifest part of the Beatles' arsenal from the very beginning, and yet, it is used here in the (shall we call it) Late-Middle-Period to very different effect than it had been back in the days of "Love Me Do", "P.S. I Love You", and the like.
Toward the end of the second verse there's quite a blooper. It's hard to unravel what was the respective cause and effect of it, but it sounds like between John's behind-the-beat delivery of the words and a hesitating screw up of the bass part by Paul right where the chord is supposed to change back to G in measure 8, they manage to add a dizzying excess pair of beats or so and still keep going. I suspect that this was unplanned but kept in the final version anyway because of its serendipitously appropriate off-kilter effect in context.
Measures 6 - 7 feature an implied superimposition of G over the C chord similar to that seen in "Paperback Writer".
Near the beginning of the third verse (around 1:20 into the track) there is what sounds like a faintly sounded "cueing beep". Was this supposed to be a half-hearted anticipation of the similar effect near the mid-point of "Tomorrow Never Knows" (you know, the thing that sounds like 'at the tone the time is ..."), or is this some kind of subtle clue that this song actually dates from the Twickenham "Get Back" sessions of January 1969? (just kidding!)
Refrain
The refrain is twelve measures, and is built out of a repetition of the same (again, non four-square) six-measure phrase:
--------------------- 2X ----------------------
|G |- |C |- |G |- |
I IV6/4 I
[Figure 91.4]
This section conveys a sense of ecstatic slowing down even though the tempo here is the same as it was for the verses. This effect is created by the change of beat for the first four measures from its erstwhile bounce to something more plodding and regular, combined with the suddenly with the slower harmonic rhythm of the section and the yawningly stretched out vocals. At the end of this section, the illusion of speed change is spun in the opposite direction by the way in which you feel an acceleration when the bouncier beat resumes in the final two measures.
The time warp effect is pushed still one step further in the second refrain by the addition of slow triplets to the bassline in the first four measures. Yet again one more example of a technique we've seen in so many earlier Beatles' songs, that is recycled here to a different, more strange effect than usual. Looked at from the opposite perspective, you might say that while a song like "Rain" makes you "know" we're not in Kansas any longer, it still does seem like the Boys sure wanted to take along a lot of their same old clothing for the big trip.
We have the same "elusive" kind of C6/4 chord in this refrain as we saw in "Paperback Writer". This time, also it is superimposed over open fifth G-Major drone in the lower parts.
Outro
The outro commences with what seems at first like an ad-libitum "general pause" and a short passage for drums and bass guitar. If you count along carefully you discover though that the entire thing is quite in tempo, and exactly three measures long.
What follows at this point is the unprecedented (and in retrospect, historically significant) trailing vocal of John's, dubbed over the backing track by playing a tape of his earlier vocal in reverse. The actual splicing and mixing in of this special effect was done very smoothly, especially by the standards of 1966 technology. No pops, no clicks, no sudden change of ambiance, etc.
If you have any doubt about the technique used here, you can either spin your turntable backwards, or transcribe the trailing vocal part and sing it yourself in reverse. The only suspicious thought I have concerns the sustained sung note C which occurs fairly well into the fade-out, and which, for the life of me, I cannot find the counterpart of in the original "forward" vocal.
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6 Some Final Thoughts
As ground-breaking as this single was, it somehow didn't turn out to be so record-breaking on the charts. Don't get me wrong; by the standards of mere mortals, the single did just fine in terms of chart position and copies sold. But by the standards of Beatlemania, it didn't come close to some of the really big hits. Wha' happened!? Were these two songs, at the time, perhaps a bit too original, or could it have been the opposite — were we all becoming a bit blasé where the Beatles were concerned?
I can only speak for myself, and indeed, I'll be the first one to admit my own experiences may not be typical; ... but I know they're mine

A warning though — unbridled soppy nostalgia runs rampant in the next couple paragraphs. You may want to turn back now.
The first time I heard "Paperback Writer" was from a jukebox in the Seagull Coffee Shop, on Brighton Beach Avenue (under the El, and not far from the boardwalk), sitting with a group of extended friends at a couple of tables pushed together, all of us wallowing in the euphoria of a terminal case of High School Senior-itis; and this new song by the Beatles was our soundtrack that late spring afternoon . It's strange how after all these years I can still remember pausing for a moment to acknowledge it with a head nodding "oh well, will you listen to that!", but then also quickly diving back into the conversation that had been interrupted. Funny how I can't remember a thing about the contents of that conversation, yet I do remember the music; vividly!
Within two months, things changed radically. I remember coming home from my stint as music counselor at a "sleep away" camp, flipping on the newfangled "stereo" receiver I had been given as a graduation present by my parents, tuning in the radically new upscale FM rock station (Scott Muni on WNEW, no fooling) and hearing for the first time the Boys' really new double-A side; "Yellow Submarine" / "Eleanor Rigby". By this time, no one was blasé about it any more, or in the least.
But at this, all excess reminiscence aside, I'm getting way ahead of our story
Regards,