Some years ago, up late on one of those winter nights when dark seems to fall a few minutes after sunup, I sat in front of my keyboard, nursing a hot beverage. I couldn’t concentrate on writing, so I switched on WMUA 91.1 FM, the UMass-Amherst station.

To my ears, there’s nothing so compelling as the decidedly non-commercial radio programming that beams out of colleges. I listen to college radio to be surprised, to have my ears regaled with things I would never discover on my own. The show wasn’t one I would normally seek out, a hip-hop show that felt like a late night dorm gathering of the students I then taught. The DJs rambled like a couple of half-in-the-bag braggarts while a dull beat looped on and on.

I was ready to twirl the big dial when someone called in to the DJs, asking to freestyle over the beat. Not smart, I thought. You’d have to be crazy to volunteer for an opportunity to fail in such a widely broadcast fashion.

But I should have amended that to read, “You’d have to be crazy or really good.” Whoever that kid was, he took to the waves with blazing abandon. He wasn’t just reading something he’d written—when a DJ started dropping in commentary, the kid interacted with him, spinning in new directions with his fast-paced delivery. I got my surprise for the evening, all right. The rhymes he dropped in fell fast and furious, often smart, often funny, a nimble display of verbal improvisation like few I’d heard.

Rap gets a bad rap. It can, at its worst, sound like a too-easy, even haphazard piling of words onto rhythm, a monotonous setting for low-stakes ego-boosting. And sure, there are MCs out there who deliver just that. I hadn’t paid a lot of attention to rap when I heard that crazy freestyler, obsessed as I was with guitar-based music, but that extraordinary display was the dawning of a new appreciation. That appreciation has expanded to a deeper understanding thanks to a recently release book called How to Rap, by Paul Edwards, holder of a master’s degree in postmodernism, literature and contemporary culture from the University of London.

That kind of from-the-academy view might sound like an unlikely fit when it comes to explaining the finer points of a genre full of ever-changing slang and stories of life on the streets. In some ways, that’s true—early on, Edwards tackles subjects that are overly broad, getting his extremely long list of high-profile interviewees to comment on, for instance, notions like “Life is a great source of material.”

Beyond those first awkward pages, though, Edwards heads into nuts-and-bolts matters in a way that breaks down just what’s going on in rap in deeply revealing manner. His authorial presence is slight—he often offers brief commentary, relying instead on a long parade of quotations from practitioners. Edwards nonetheless gets into aspects of rap that wannabe MCs need to know.

As impressive as freestyling is, it’s clear from How to Rap that most giants of the rap world are engaged in a deliberate and highly thought-out art. There’s talk of how to diagram delivery of lines over music, and it’s there that things get really interesting. Some of the MCs Edwards interviewed know terms from music theory, and others express the same ideas in ways that are fascinating to read. Vast Aire of Cannibal Ox, for instance, explains how he notates rests: “I put two back slashes—that means to chill, let the beat drop, and then come right back in on time.”

It’s clear that many rappers approach their art as a discipline, studying dictionaries, sifting through hundreds of beats to find the right match, and employing elaborate rhyme schemes. Aspiring rappers can learn plenty from Edwards’ book. Critics of rap will find much to challenge their notions of the genre’s simplicity, from the deliberate placement of lyrics in front of or behind the beat to breath control work and fascinating notions like that brought up by Shock G: “My friend Saafir, a West Coast underground champion, once told me he gets his word patterns from jazz horn players like Charlie Parker and John Coltrane [and] he swings his words around the beat rather than on it.”

In a lot of ways, Edwards’ book paints a picture of rappers who may look to fans as if they live dissipated lives, but who create that image in some counter-intuitive ways. Says Omar Cruz, “I read a lot—I’ve always loved reading. Just reading, period, is gonna help your vocabulary. It doesn’t matter what you read just as long as you’re reading—your vocabulary expands.”

Whoever that freestyling kid on the radio was, it seemed clear that his dorm room was full of books. Whoever he was, he kept me coming back to that late night show, ready to hear the dazzle of a whole new kind of word play.