You know the songs.

“Mandy.” “Copacabana.” “Weekend in New England.” “I Write the Songs.” “Could It Be Magic.”

You know the singer-songwriter behind them, and the hundreds more that became part of the fabric of American pop music over the over the past 40 years.

He is Barry Manilow, of course, the accordion-playing, gangly kid from Brooklyn, New York, who learned to play the piano and write songs, and eventually skyrocketed to the top of the charts, amassing a music catalog as relevant and timeless as they come. Rolling Stone proclaimed him “the showman of our generation” and more recently, the Foo Fighters’ David Grohl proclaimed: “Barry Manilow is the coolest mother—– in the world.” Manilow was among the chorus of glitterati who gathered for the final episode of “The Colbert Report” in December.

That’s not to say Manilow hasn’t had his share of detractors; the line has always been clearly drawn in the sand between his diehard fans and equally diehard haters. To the latter, four words speak volumes about Manilow’s staying power: 80 million records sold.

And those records ran the musical gamut, from singing with the big bands to singing Sinatra, pop, jazz, R&B, swing, the Great American Songbook and Broadway show tunes.

This year, Manilow received his 14th Grammy nomination (he won for “Copacabana” in 1979) — for best traditional pop vocal album for the little-known, piano-driven “Night Songs.” It marked a milestone in his career — he’s been nominated in each of the past five decades (Sunday night’s statuette went to Lady Gaga and Tony Bennett for “Cheek to Cheek”).

“It was a huge surprise [that the album was nominated] because this album was so under the radar,” Manilow said in an interview just days before the Grammys were awarded, in which he accurately predicted the win would go to Bennett. “This was an album I did for myself and my friends. And they loved it. … [But] There was a time last year that I needed an album quickly for the label and my friends and manager said, ‘Let’s do this one.’ So we [released it]. It didn’t even enter the charts, that’s how under the radar it was! The Grammy nominating committee somehow found it.”

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Not so “under the radar” was the release of “My Dream Duets,” which debuted at No. 4 on the Billboard Top 200 last October, making it Manilow’s 15th Top 10 album. The CD features Manilow singing with the late Whitney Houston, John Denver, Judy Garland, Louis Armstrong, Sammy Davis Jr. and Marilyn Monroe, among others. The album, one of the most challenging of his career, Manilow admitted, was the right project at the right time, and literally a dream come true.

“My record company asked if I would do a duets album. Everybody and their mother is doing duets albums,” Manilow said. “So I was like, how do I make my duets album different? And I came up with this weird idea of making duets out of old records that never were duets. [My team] didn’t think it could be done, but they did it. I had a whole team of technicians working on it.”

The technological side of the album was a Herculean task, the 71-year-old Manilow said. Even narrowing down the 11 songs that made the final cut resulted from a very involved process of elimination.

“I did 35 rough demos, with 35 different singers [including] people like Fred Astaire, Bing Crosby, Lena Horne, the Bee Gees, Dan Fogelberg’s ‘Longer Than,’ ” Manilow said.

“We had so many [obstacles to overcome] with this project. What we were stuck with were very scratchy old records. … We would have to replace the orchestra on those old records, and we really didn’t think it could be done. [We found] a company that could do that and leave me with just the vocals. We had to put brand new orchestra under each song as well as my vocals. … Normally it takes about two months to do an album; this one took about six months. Technically it was a bear. It wasn’t just writing a song and arranging it and going into the studio and singing it.”

BARRY MANILOW

with Dave Koz

When: 7:30 p.m. Feb. 14

Where: United Center, 1920 W. Madison

Tickets: $19.75-$249.75

Info: Visit ticketmaster.com

Manilow is kicking off his “One Last Time!” tour on Feb. 11 in Omaha, Neb., calling it the end to his full-out, big tours. The road show comes to the United Center for a Valentine’s Day concert Saturday night.

Here is more of what Manilow had to say about his dream duets and his career:

Q. What’s it like to sing with all these legends?

A. Singing with these people — they were there in my headphones, but it was as if they were singing next to me. I mean, singing with Whitney [on “I Believe in You”], I was reaching for the Kleenex. These are all people I admired all my life. To be able to sing with them. Trying to figure out where I should sing, where I should solo, where I should harmonize.

Barry Manilow | Photo by Kris Connor/Getty Images

Photo credit: Kris Connor/Getty Images

Q. When you stripped away all the music, what were their vocals really like? Did you have to do any technical wizardry on their voices?

A. I didn’t touch their vocals. These are legends not by accident. These were great singers, great personalities. You put on John Denver and there’s no one who sounds like John Denver. You put on Judy [Garland] and there’s no one who sounds like her.

They were musicians — in time, in tune, acting their lyrics. Those were the days you acted a lyric because you’d have a good lyric to act. … To be able to sing these beautiful, well-written songs. I wanted to honor each of them. I didn’t want this to be my album, I wanted this to be their album, show the listeners why they were legends.

Q. How did you approach all the new orchestrations, reworking, for example, Henry Mancini’s iconic “Moon River” with Andy Williams?

A. Re-doing the backgrounds was fun for me. The original backgrounds were old-fashioned sounding. I wanted to stay true to [the] orchestrations but make it sound a little more current. The sound of the orchestra is very today. … there are different chord changes. I came up with a different beginning, ending and bridge. It was about change, but it also was about honoring all those orchestrations as well as the singers. I wasn’t gonna make a cha-cha out of “Moon River.”

Q. What was it like to “sing” with Marilyn Monroe, and was her voice really that good?

A. If you listen to the original of that record, that was the one where I really dove in and redid that record. It has a whole different ending [from the original version]. It doesn’t have that middle [of the original]. So it doesn’t have any jazz in it. But I thought doing Marilyn Monroe, that would be wild. She sounded great on it. We never touched her vocals.

Q. Did you get the chance to meet Sammy Davis Jr.?

A. Never got the chance. He was a bit before my time. I would see him on variety shows. He was the most talented human being of his time. And I learned that [“Candy Man”] was his least-favorite song. He hated it. Yet is was his biggest song, his only No. 1 song. This was one of the cuts where he was in my headset and I really felt like he was standing next to me.

When I first [heard] the song. I must say it wasn’t one of my favorites. But when I started studying it and started playing it, it actually moved me to tears. It was so well written — the melody, the chord changes, the background vocals. People don’t write like this anymore. I never really paid much attention to the song and there it was, another beautifully written pop song, and I can’t say that about many of them today.

Q. How will these duets translate to live performance on this tour?

A. We made four videos on four of the songs: Louis Armstrong, Judy Garland, John Denver and Whitney. So we’ve rehearsed all of them, and I’ll flip them around. I can only do one per show. It all depends on what spirit moves me.

Q. So many artists say it’s their final tour. Is this really Barry Manilow’s last tour?

A. This really is the last BIG tour. It’s been 40 years of big touring, and this is the end of that. It’s not the end of making records or doing one-nighters or Madison Square Garden for a night or two if I have a record to promote. But it’s the end of those big tours that keep me away from home for weeks at a time.

Q. At the end of the day, which of these duets touched your soul the most?

A. Two of them. Whitney just kills me … just gone too soon. And Judy [Garland, on “Zing! Went the Strings of My Heart”]. I wish I had known her. She’s my kind of entertainer. As a singer, there’s nobody who tops her. She’s got music in her bones. She was surrounded by the greatest arrangers. As a singer, there’s no one more real or truthful. She was 4-foot-11 of talent.

NOTE: As part of his Manilow Music Project, the singer is donating a new Yamaha piano to kick off a musical instrument drive for Chicago Public Schools. Anyone who donates a new or gently used musical instrument to the United Center box office (through Feb. 14, 11 a.m to 6 p.m.) will receive two free tickets (valid for pre-selected seat locations) for Manilow’s Saturday night concert in Chicago.