DETAILS: You're releasing a record on September 17 with the Roots. You and Questlove are both magpies—collecting, playing, and sharing music from across genres. Was it love at first sight?
Elvis Costello: I've been on Jimmy Fallon, where the Roots are the house band, a number of times. Playing with them seemed effortless, and I enjoyed it enormously. One time, they dug out an arrangement of a song I hadn't played since 1978, and they made their own version of it. They had that kind of approach, digging down deep to bring up something new. [After another show], Quest said some little enigmatic thing to me as we left the set, and the next thing I knew we were making the record.

DETAILS: Do you remember what it was?
Elvis Costello: I do, but I'm not going to tell you. It's like the thing Bill Murray says to Scarlett Johansson at the end of Lost in Translation. It's like the secret key, but it's not important to share it. It would prejudice people's way of thinking about the music.

DETAILS: Your father was a musician in Britain's answer to the Glenn Miller Orchestra. What did he teach you about music?
Elvis Costello: I have a very strong memory of him having stacks of records and sheet music, and him rehearsing in the front room. My mother was working in a record shop at the same time, so the awareness of different types of music, different sounds, rather than having all these boundaries between the music, that's what I've come to understand. When people talk about genres and stuff, I don't even know what they're talking about. But there was not a lot of rock 'n' roll in the house. Our parents didn't think it was very groovy, and I tend to agree with them. If you grew up with Charlie Parker, Bill Haley wasn't very hip.

DETAILS: You were raised Declan Patrick MacManus in London and then Liverpool. You now live in New York and Vancouver. Do you still feel British?
Elvis Costello: I've never felt British. I'm just not interested in national identity. I don't know why. It's a petty thing, but I wouldn't join the Scouts when I was a kid, 'cause you had to swear allegiance to the queen. I'm just not a royalist. I think it's idiotic, a hereditary principle.

MAN OUT OF FRAME: Right, Costello in London's Royal Garden Hotel with his custom 1965 Fender Jazzmaster; left, his guitar case.

DETAILS: You famously sang about Margaret Thatcher, "I will stand on your grave and tramp the dirt down." How did you react when she died?
Elvis Costello: It doesn't really change anything. What am I supposed to say? What other line would you like, other than the one I already wrote? On a personal level, I have difficulty wishing anyone ill, even someone who represented so many negative forces and did so much damage to the country, like she did.

DETAILS: In 1977, on Saturday Night Live, you stopped playing "Less Than Zero" and started playing "Radio, Radio" [a controversial song about iniquity of the music business that got Costello banned from the show for a decade]. What were you doing?
Elvis Costello: They've run that clip forever, and every time anybody does anything outrageous on that show, I get name-checked. But I was copying Jimi Hendrix. Hendrix had done the same thing on [BBC's] the Lulu Show, when he went into an unscheduled number. I remember seeing it and going, "What the hell's going on?"

DETAILS: You stopped drinking alcohol 17 years ago. Why?
Elvis Costello: I just didn't like the taste.

DETAILS: Did giving it up improve your life?
Elvis Costello: If I was missing it, I would be drinking, wouldn't I? I guess I didn't need it anymore. I don't know if I ever needed it.

DETAILS: Has the Internet liberated you as an artist or made your life more difficult?
Elvis Costello: The Internet is overrated. It's much smaller an innovation than people think it is. I don't think it's changed the way anybody makes music. Now, if we're talking about selling music . . .

DETAILS: You're fond of the maxim that writing about music is like dancing about architecture. Have you ever read anything about music that was interesting and true?
Elvis Costello: I mean, I've read lots of books about music, and some of them have been really beautiful. I read two big volumes about Elvis Presley by Peter Guralnick. Articles? I don't know. People always insert themselves in them. It's not really reporting. They're using all the wrong words to describe the music. You literally don't know what they're talking about.

DETAILS: In 1979, you were involved in a drunken argument with Stephen Stills' band in which you called Ray Charles a "blind, ignorant n*****." You later apologized, but did you ever straighten things out with Charles before he died?
Elvis Costello: I'm not going to answer that.

DETAILS: But now you're writing a memoir, which will require some opening up. How's it going?
Elvis Costello: It's going really well . . . but nobody's going to believe you, whatever you say. They just believe what they want to believe. They want to believe I'm a racist. Or they want to believe I'm a misogynist. So let them fucking believe it. I'm not going to argue with my own past. Explain all that shit? They'll have a long fucking wait. Why write down again what other people have already written down? People come around and they've got the audacity to quote something I said 30 years ago and say, "Do you agree with that?" No, of course not, because of all the experience that came after. Who the fuck does that to anybody else? It's an idiotic idea that everyone remains the same, and it's based on the show-business principle that you should be young forever, you know? And that's not true.

DETAILS: So, then, what is the book about?
Elvis Costello: I'm interested in this funny deal between music being mundane, in that it's an occupation, and magical, in the way that it's a vocation. It's like being a priest. That strange alchemy, with the water and the wine and the wafers—there's a bit of that about it. I so easily could have been a priest with this face. Father Declan. I'm named after a priest. Anyway, I'm kidding you. You know I'm kidding. Half of what I say is meaningless.