The easiest way to split up the Beatles’ career is into two parts: the early moptop days and their “art” period. Harder is figuring out which record marks the transition. Rubber Soul is the most obvious candidate, with its layered, sardonic songs. A more conservative choice is Revolver, by which time their evolution beyond “Love Me Do” was indisputable. But Help!, released fifty years ago today on August 13, 1965, is the first record to make the wealth of artistry they had yet to explore plainly obvious.

For one, their songwriting had grown by leaps and bounds. John Lennon, at that time the group’s best lyricist by a mile, was waxing more introspective. “Help!” is a plea of desperation that might sound like a love song until you realize it’s never explicitly addressed to a woman. “You’ve Got To Hide Your Love Away,” with its masochistic entreaty for “all you clowns” to gather around and make him feel like shit, continues the self-loathing of Beatles for Sale‘s “I’m A Loser.”

Their songs also grew in thematic complexity. “You’re Gonna Lose That Girl” finds John threatening to steal a friend’s lover if he continues neglecting her, but the glee in his voice makes it clear his motives aren’t altruistic. And a rapidly maturing George Harrison contributes a compelling portrait of a toxic relationship in “You Like Me Too Much.” His girlfriend keeps leaving and coming back; he admits he deserves to be left, but he’s too into her, so the cycle continues.

One major outside influence might have catalyzed this growth. The band met Bob Dylan in August 1964, as they were recording Beatles For Sale, and his influence is plain in a few spots. “You’ve Got To Hide Your Love Away” is a blatant Dylan pastiche (“feeling two foot small” is ridiculously on-the-nose). Even Paul sounds a bit Dylanish on the country-flavored “I’ve Just Seen A Face” – check out those “lai-da-da-dai”s.

But Dylan also introduced the band to pot, and it’s no coincidence Help! contains some of the “trippiest” material they had yet recorded. “Ticket To Ride” contains a contrast of ominous drone and a pop melody that presages their headiest work on Magical Mystery Tour (“Blue Jay Way”) and The Beatles (“Dear Prudence”). And George Harrison’s processed guitar on “I Need You” is one of the most beautiful sounds the Beatles ever recorded, especially as it tearfully lilts towards the end.

But the most prescient song comes second to last. “Yesterday,” a stunning, brief ballad, is Paul McCartney alone with a string quartet. It’s the first of a trilogy of sad, string-oriented songs the band would record, and it’s also the first song a Beatle would record alone. It’s also a compelling argument for the devil-angel John-Paul dichotomy; Paul’s speculation that “I said something wrong” is a mea culpa John would never own up to.

That said, these leaps down the rabbithole only represent a fragment of Help! There are still two covers, both solid but still filler. “It’s Only Love” is maybe the Beatles’ cheesiest ballad, and “Tell Me What You See” might be their dumbest chorus. But while Help! isn’t the most consistent album in the Beatles catalog, it’s crucial as a historical document — even more so because of the number of great songs on it.