Elvis Costello agreed to sit for an interview not long ago, but where to sit was up for grabs. The place was a conference room at the Friars Club, the longtime Manhattan show-business hangout where every chair has a nameplate for a member, and Mr. Costello methodically looked at the dozens of them lined up around the walls: songwriters, singers, actors, comedians, vaudeville acts. Lorenz Hart was a contender; so was Damon Runyon.
But in the end, Mr. Costello chose the seat named for Sammy Cahn, the lyricist for "Come Fly With Me," "Call Me Irresponsible" and "Guess I'll Hang My Tears Out to Dry." It turned out that Mr. Costello had tried to collaborate on a song with Cahn, who died in 1993. Nothing came of their meeting, but it had been one more opportunity Mr. Costello couldn't resist.
He has collaborated restlessly and relentlessly. The list keeps growing: Paul McCartney, Burt Bacharach, Brian Eno, George Jones, the Charles Mingus Orchestra and lately Diana Krall, whom he married in December and recently assisted in writing songs for her new album, The Girl in the Other Room.
Why so many hookups? "Why not do it?" he said. "Who would turn down the opportunity? It's not the opportunity to make more money or to be thought of as bigger and better than you are. It's just to enjoy the experience of working with different people."
The results have been copious and inevitably inconsistent. Mr. Costello has honored established genres -- writing smart, exemplary rock songs, country weepers, soul testimonies and pop ballads -- and he has labored over busily cerebral misfires. He has written lyrics heavily clotted with verbiage and melodies beyond the agility of his husky baritone; he has also pulled off startling emotional coups as both a shouter and a whisperer.
Mr. Costello doesn't just bounce between extremes, like following his return to aggressive small-band rock, the 2002 When I Was Cruel, with an album of subdued, meticulously understated ballads, North, in 2003. He follows his whims like someone who wants to add his own works to every cranny of a huge record collection. It is by no means a strategic career path; it's a series of impulses and happenstances, followed through by diligent work as Mr. Costello strives to master idiom after idiom. He has been a perpetual apprentice, with enough of a catalog and a core audience to sustain continued experimentation.
Listeners and critics who expect performers to stay in their niches have repeatedly dismissed and then grudgingly rediscovered him, a cycle that clearly rankles Mr. Costello. "Sometimes the accusations of vanity about working in other areas are just so stupid," he said. "And a lot of it is down to the fact that you do something over a long period of time or you do something that's very heartfelt. Sometimes you want to grab somebody by the throat and say, 'This is real life.' You get defensive about things you love."
Mr. Costello will turn 50 on Aug. 25, and he had originally booked a date at Carnegie Hall to celebrate the birthday. Then came a better offer: three nights at the Lincoln Center Festival this week, with three different ensembles and more than five dozen songs to learn, among them at least half a dozen that Mr. Costello has never recorded. On Tuesday, he is to sing with the Metropole Orkest, a 52-member jazz orchestra from the Netherlands that combines a big band with a string section. The concert will include arrangements by the guitarist Bill Frisell, by Mr. Costello's longtime pianist Steve Nieve and by Sy Johnson, who has done arrangements for the Mingus Orchestra.
On Thursday, it's back to rock. Mr. Costello is to perform with the Imposters, who include Mr. Nieve and the drummer Pete Thomas, both from his longtime rock band the Attractions, plus a bass player, Davey Faragher, who joined them in 2001. They have just completed an album at Sweet Tea Studios in Oxford, Miss., The Delivery Man, that is due for release in September, and they are likely to perform some new songs. On Saturday the Brooklyn Philharmonic is to perform Il Sogno, an orchestral score Mr. Costello wrote for an Italian dance company's adaptation of A Midsummer Night's Dream, and to accompany Mr. Costello in full orchestral arrangements of his songs. A recording of Il Sogno conducted by Michael Tilson Thomas is also due for release in September.
By now, Mr. Costello has come to expect flak for jumping genres -- most of all, perhaps, for Il Sogno. Big symphonic statements by rock songwriters like Mr. McCartney, Joe Jackson and Trey Anastasio have been greeted with shrugs and skepticism from both the classical and pop camps. "I don't really have any big ax to grind," Mr. Costello said. "I don't have any big statement to make. Every single time you cross a border, somebody says, 'Don't go over there.' But I don't care anymore. Why am I doing it? Because I can. Am I doing it to make myself look more serious? What? Are you kidding? I've been taken way too seriously since I started. There are much easier ways to be taken seriously than to write for an orchestra."
"All the music comes from the same place," he insisted. "It's just the trigger that's different."
The Delivery Man revs up the already ferocious attack the Imposters showed on When I Was Cruel. While the songs were written before Mr. Costello arrived in Mississippi, the album is steeped in Southern Americana: the gospel-rooted grooves of Memphis soul, touches of pedal steel guitar, Southern-rooted guest singers including Emmylou Harris and Lucinda Williams and the storytelling that Southern soul shares with country music.
Initially, Mr. Costello had planned The Delivery Man as an album that told a story, along the lines of Willie Nelson's Red-Headed Stranger. The setting is a small town, perhaps in the South; the main characters are three women. "It's an imaginary place but so is everything these days," he said. "But they are three particular types of person. One who imagines herself wilder and more dangerous than she is. Another who is very restrained and pious. And a young woman, a young girl really, a teenage girl who hasn't decided which way she wants to go in life. And they all in different ways look for something that they don't have in this guy who just passes through their life."
Along the way, though, Mr. Costello decided to break up the narrative for musical continuity, and other ideas crept into the album: "Monkey to Man," a late-breaking sequel to the New Orleans songwriter Dave Bartholomew's misanthropic 1954 single, "The Monkey," and "Bedlam," which juxtaposes the Nativity story with current strife in the Middle East.
"You're kidding yourself if you believe it when people say, 'Oh, that's a political song,'" Mr. Costello said. No. A political song is one that if you played it to Donald Rumsfeld, he would give up his career and enter a monastery. That would be a political song -- one that affected him so deeply that he would renounce his view of the world. I don't think anybody alive is capable of writing that song. So all you're doing is writing things that matter to you."
The album was recorded quickly at Sweet Tea, a small stone building where the band set up and played as if it were on a stage. "No screens, no headphones," Mr. Costello said. "Using stage monitors. Just dealing with the bleed. You just turn up the instrument that's too quiet. That's all we did.
"It's the kind of rock and roll music that a man of my years can play without embarrassment. It doesn't sound processed. It's some guys playing in the room. I hate that expression good old rock and roll. When did it become good and when did it become old?"
He wrote the score for Il Sogno in equally low-tech style: working with a pencil and writing out every instrumental part in a 200-page score over a 10-week stretch.
"When I told my friends who were orchestrators I'd done that, they said, 'Are you out of your mind?' I said, 'Well obviously I am.' But I didn't know not to do it. It did drive me slightly mad. But I didn't know that I wasn't supposed to do that because I'd never read a book that said you shouldn't do that. And it sounded all right when we played it."
Il Sogno follows the narrative structure of A Midsummer Night's Dream as adapted for the Italian ballet company Aterballetto. It's a rhapsodic piece full of shifting moods, with moments of eerie delicacy and of comic pomp. Mr. Costello assigned different styles to the three different classes of characters: "mock grandeur" for the nobles of the court, folk-like melodies for the workers and swinging tunes, with a streak of big-band jazz, for the fairies.
"When I first heard it," said Mr. Thomas, who conducted the London Symphony Orchestra recording, "I thought this is a guy who really is in a process of searching out a lot of interesting answers in music. The interesting thing is that he doesn't always use melodies to hold the thing together. Sometimes he just uses a kind of flavor of harmonic language, which is quite elusive and subtle, especially as he evokes the dream world. There's some music that is so wondrously adventurous and non-tonal that you'd never suspect Elvis Costello has written this, because it's so out there."
Mr. Costello said: "I'm not concerned with this music's relationship to my own past. Perhaps you can tell it's me, but I hope it doesn't remind you of another year in my life. I have absolutely no nostalgia about my past. I never liked being young, and I feel absolutely at a peak of my life. There are some terrific records that I'm glad I made. But I don't want to stand and fall on a handful of songs because there are still a lot of songs to be sung."