In ninth grade I was at a party and Becky Davis put on the twelve-inch single of New Order’s “Everythings Gone Green.” Someone had a spare ticket to hear the Kronos Quartet, and they played something by Conlon Nancarrow. After reading a thing about him in the newspaper I bought a cassette of Frank’s Wild Years by Tom Waits. In college I walked by someone’s dorm room and then stood in the doorway listening to Sound Sun Pleasure by Sun Ra. I bought a used copy of the 6ths’ first album, Wasps Nests, because it looked cool. This violinist I knew made me buy a Scriabin symphony and I honestly thought there was something wrong with the volume knob at home. Morton Feldman, Piano and String Quartet, when I lived in New York, I don’t remember why. Now this thing, this marvel of a thing.

It’s not the regular musical epiphany—the first time you hear Johnny Cash, say, or Purple Rain. I’m talking about hitting the tip of an iceberg, when you hear music you didn’t know you could hear, a new genre or a combination you hadn’t dreamed of, and when your ears bonk into it, it’s not enough just to get the album. You want everything like it. I spent all my summer job money on New Order imports. I dove into Nancarrow—boy, his pieces for player piano will take your head apart— because it hadn’t hit me until that show that you could like difficult music not as a pose or an intellectual exercise, but because it rocked ten times harder than the Stones. The gypsy blues carnival of Waits was an idea I never would have dreamed up, or the noncerebral naïveté of Sun Ra’s clatter, or the way Stephin Merritt made couplets, or the way Scriabin’s drama never, never lets up or Feldman’s never begins. These were all brand-new things to me, detached from anything else I’d heard previously. They led me down a million paths, from the pile of Sun Ra albums I own—more than any other artist— to playing on the second 6ths record, to writing thirteen children’s books with the Scriabin cranked. But the real magic of this thing is that the path’s a sort of Möbius strip. I never thought of music like this, but the new thing about it is that it doesn’t go anywhere. It’s already arrived.

I’m trying to say what it’s like before I tell you what it is, because when I first heard about it I thought it sounded dumb, and only when I read several interviews with musicians who said they were having trouble working because of the way it made them think, that I bought one and set it up. It’s the size of a deck of cards. It comes in six colors and you don’t get to choose. It looks like a slightly campy crappy Chinatown transistor radio. There’s a jack for headphones, which I don’t recommend, and a...