The mini-essay begins with a meditation or disquisition on the role of yeahs in this song in particular and the Beatles music in general, replete with a count of the number of yeahs in this song, and which one is Sheffield's favorite (I've long agreed with his choice).
But it quickly turns out that this chapter is not about yeahs but about the Beatle's love of American girl groups, ranging from Rosie and the Originals (I love their "Angel Baby" so much I from time to time listen to the dozen or more excellent covers on YouTube) through the Shirelles, the Motown girl groups, and of course the Ronettes. (The first piece of music journalism I remember ever being impressed with was a review - maybe in one of the student newspapers - of the Ronettes' appearance at CCNY, where I was a student, around 1964, and how the jeans of every guy in the audience tightened as Ronnie began singing and moving.)
The Beatles expressed their admiration of these groups by injecting the girl groups' vitality into their (the Beatles') yeahs. And in a brilliant analysis of a single line - one of Sheffield's specialities - he explains why the Beatles concluded "It Won't Be Long" with the line "Till I belong to you" rather than the more expected "Till you belong to me": it's because the former is what a girl group would sing.
There's Brill Building, Ellie Greenwich (I mentioned my connection to her in my first review of this book), and all kinds of things that show Sheffield is adept not only in understanding the Beatles but the music that inspired them, and which they incorporated and ultimately built upon rather (than is often wrongly said) they replaced.
The next chapter is about why Ringo was crucial - and that deserves a review of its own, to come as soon as I've read the chapter, which won't be long, yeah.
See also Review of Rob Sheffield's Dreaming the Beatles 1 of X: The Love Affair ... 2 of X: The Heroine with a Thousand Faces ... 3 of X: Dear Beatles ... 4 of X: Paradox George ... 6 of X: The Case for Ringo ... 7 of X: Anatomy of a Ride ... 8 of X: Rubber Soul on July 4 ... 9 of X: Covers ... 10 of X: I. A. Richards ... 11 of X: Underrated Revolver ... 12 of X: Sgt. Pepper ... 13 of X: Beatles vs. Stones ... 14 of X: Unending 60s ... 15 of X: Voting for McCartney, Again