In the way people remember where they were and what they were doing when JFK was shot, or when the Twin Towers collapsed, I can recall where I was and what I was doing when I heard a revolutionary piece of music. I have had at least 12 moments of this kind in my life—moments when I heard for the first time in some place (a bedroom, a record store, a cafe, a car) a song or a beat that was completely new to my ears and understanding of music. The French philosopher Alain Badiou describes an "event" as a rupture in the known and stable state of things. The rupture opens a void. In this void, what is radically new is on its own. It's like an astronaut floating away from the mother ship, floating into the growing blackness of the void. But soon, everyone catches on, and the void is closed, and the new becomes recognizable, understandable, identifiable.

My first experience of this kind of event happened in 1979 in Sharptown, Maryland. I was 10 at the time and learning the flute in a music class taught by an eccentric black American woman. (My memory has retained everything about this teacher—round figure, radiant face, smooth and spotless brown skin—but her name.) The lessons happened behind Sharptown Elementary School's main building, in what looked like a large shed or the kind of structure you'd expect to find on a military base: made from cheap materials and easily assembled and disassembled. One sunny day, the teacher was late to class, which began at around 3 p.m. We, the students, waited and waited, talked and talked, got louder and louder, and the room was on the verge of chaos when the music teacher burst in through the door and ordered us to gather around her desk. On the desk was a record player, and in the shopping bag she carried was a record. She pulled the vinyl out of its sleeve, placed it on the turntable, selected a rotational speed, turned it on, set the needle on the disk's edge, and after a moment, something strange began to happen to us.

We all knew the music, but we did not know what was being done to it. The music was "Good Times" by Chic. But the singers had been replaced by men who were kind of talking. What I and the other students found so difficult to understand is this: Was this still Chic? Was Chic involved in this? And if not, why would anyone talk-rhyme over someone else's music? And if you didn't make the music, were you even a musician? If not, what were you? The teacher breathlessly explained: It's the next big thing. The group, the Sugarhill Gang, is doing something that is really happening in New York. It's called rapping, and the track is called "Rapper's Delight." I could not make sense of what she was saying and the music she was playing. As the record turned and turned (this rapping seemed to go on forever), I drifted through the void.

The second experience (or event) happened in Harare, Zimbabwe, in 1987. This time, I was a teenager and alone in a cottage to which my parents banished me when they had had enough of my loud hiphop. "No more boom-boom in the house," my mother complained. "Move into the cottage and listen to all the boom-boom you like." The cottage, which was a safe distance from the house, had a queen-size bed, a bathroom, a couch, a coffee table, and French windows. Above my bed was a poster for Betty Blue, a French film that I desperately wanted to see, and behind the poster were flat spiders that were harmless and seemed evolved for the slim niche behind posters.

One evening, there was a knock on my door. I opened it and found a friend, Tendai, who had just visited Dumisani and Akim Ndlovu, two very rich kids whose father owned a whole school in downtown Harare. The week before, the Ndlovus had visited New York City and recorded on cassette tape Red Alert's Kiss FM master mix and Marley Marl's WBLS master mix. (Five years later, the Ndlovu brothers moved to the States, formed Zimbabwe Legit, and released Doin' Damage in My Native Language, an EP that contained a remix by DJ Shadow.) I knew the Ndlovus very well, but I was not a part of their inner circle. Tendai was. And, most importantly, Tendai had permission to make a copy of the most desired tape in Harare on a double-deck cassette player. This tape was in his hand. On one side of it, Red Alert; on the other, Marley Marl. Though both DJs were gods to us, Red Alert was more edgy, more experimental than Marley Marl, whose show, Rap Attack, was hosted by Mr. Magic.

The Marley Marl side of the tape began with the appearance of two completely new rappers, EPMD, who, after a short interview, performed "Knick Knack Patty Wack." The middle of the tape contained the furious "It's a Demo" by Kool G Rap and DJ Polo. All was pretty normal until the end of the show. Marley Marl stopped mixing, there was a moment of silence, and then we heard something like never before. The drumming was really weird, the rapping was even weirder, the scratching was totally insane, and those churning, burning, horns—fucking hell, what was going on? We didn't hate or love it. We just didn't understand it. Public Enemy's "Bring the Noise" simply destroyed the ground we stood on. We listened to it over and over, into the night, into the blackness.

Then came 1995. I was in Chicago with my girlfriend. We were on a road trip that had taken us from Seattle to Toronto to Quebec. We were now leaving the "city of the Big Shoulders" and heading to the Bay Area (the penultimate destination). As we merged with the traffic on the freeway, something unexpected happened on the radio. It was a rocking version of Public Enemy's "Black Steel in the Hour of Chaos." My immediate impression: Sonic Youth had done another collaboration with Chuck D, or something along those lines—the singer didn't sound at all like Kim Gordon. I was confused. I found a piece of paper and a pen in the glove compartment and made a note of the song.

Two days after arriving in San Francisco, I visited a record store and learned from a knowledgeable record dealer that the track I caught on the radio was actually by an English chap called Tricky, and his new album, Maxinquaye, had just been released. I bought it on the spot, returned to the car, put the cassette in the player, and as we drove out of the city and drove toward our final destination, Seattle, toward the end of a monthlong journey, I listened to a completely original combination of musical elements. There was the singer with the hurt in her voice, the rapper with a kind of impotent anger or rage in his rhymes, melodies that were erotic but with no warmth, and a dub that lacked magic or any evocation of paradise. How did all of this come to be one? It was like sex on Venus with no atmosphere. "Overcome" played as we crossed the Golden Gate Bridge—the misty air, the low clouds, the concrete, the metal, the great abyss.