In retrospect, it’s hard to see Revolver as anything but transitional. “Strawberry Fields Forever” was still six months off — an eon by the standards of the assembly-line pace at which the ‘60s pop industry worked. Its studio experiments, exemplified on “Tomorrow Never Knows,” were only baby steps compared to the leap the band would make on follow-up Sgt. Pepper. Many of its ideas would be taken to their logical conclusions later — “Love You To” would become “Within You Without You,” “Eleanor Rigby” would become “She’s Leaving Home” (and had already been “Yesterday”).  And only a small portion of the album was particularly experimental at all. In fact, much of it remarkably conservative.

Yet there’s nothing else in the Beatles catalog quite like it. It’s the band’s darkest album, for one. John’s paranoia reached new depths on his five songs, while Paul, who also brought schmaltz like “Good Day Sunshine” to the table, delivered two grade-A bummers in “For No One” and “Eleanor Rigby” (the latter’s said to be an even group effort, but it’s obviously dominated by Paul). And where else in the band’s catalog can one find anything like the exuberant horn-pop of “Got To Get You Into My Life,” the amniotic harmonies of “Here, There, And Everywhere,” the hyper-specific protest rock of “Taxman,” or the gothic heavy rock of “She Said She Said?” In its eclecticism, creepiness, and stylistic wantonness, its closest kin is perhaps The Beatles (1968).

It’s also cousin to The Beatles in how rocky a listen it is. It doesn’t flow all that well as an album, in part because of the amount of drastically different material in a short timespan (Revolver features 14 songs, and the three longest are all three minutes on the nose). Take a gander at the first six tracks: “Taxman,” political hard rock. “Eleanor Rigby,” sad string ballad. “I’m Only Sleeping,” psychedelia. “Love You To,” Hindustani classical. “Here, There, And Everywhere,” Everly Brothers harmony-pop. “Yellow Submarine,” children’s song. It finds more consistency in its smoother, more pop-oriented back half, but this is an album that takes a while to get going.

But once it gets going, it’s something else. Save “Doctor Robert,” home to maybe the most groan-inducing use of homonyms ever committed to record, the songs from “Here, There, Everywhere” are all winners. “Yellow Submarine” is delightful and guileless. “Good Day Sunshine,” with its sprightly, confident piano lope, is irresistible. And George, developing a bit more as a songwriter with each album, delivers his first truly great song: “I Want To Tell You,” a weird little love song that uses skin-crawling discord (if you think that two-note piano riff is scary, wait until he starts wailing on the fadeout) to communicate romantic anxiety.

Some of the band’s best work can be found here. But, compared to some of the Beatles’ other classics, it’s underwhelming and doesn’t really gel into a complete statement. Its psychedelic flourishes were stunning for the time, especially on “Tomorrow Never Knows,” which is arguably the most influential psych-rock song of all time. But those spoiled by the band’s later work or the more extreme psych artists that elaborated on the Beatles’ innovations (Hendrix, for one) might find Revolver too tame. And Sgt. Pepper translated a lot of the ideas hatched on Revolver into a better album.

But even a lesser Beatles album is wont to contain some of the best pop music ever put onto earth, and Revolver has enough going for it that anyone could be in the mood to put it on over one of their more satisfying albums. Even its worst songs have charm, and there are great arguments to be made for “Doctor Robert” and “Taxman” — which I’ve always found petulant — as fine songs. I don’t blame anyone for naming Revolver as their favorite Beatles album. I also don’t blame anyone for listening to it once or twice and wondering what the big deal is.