Chicago began work on its next album August 1, 1974, at Caribou Ranch, and the results started to emerge in February 1975, with the release of the single "Harry Truman," Lamm's tribute to a president America could trust and a reference to the recently concluded Watergate scandal. Pankow wrote the sentimental "Old Days." "It's a memorabilia song, it's about my childhood," he says. "It touches on key phrases that, although they date me, are pretty right-on in terms of images of my childhood. 'The Howdy Doody Show' on television and collecting baseball cards and comic books." "Old Days" was a Top 5 hit when it was released as the second single from Chicago VIII, which appeared in March 1975.

The year 1975 marked an early commercial peak in Chicago's career, a year during which the band scored its fourth straight Number 1 album, a year when all its previous albums were back in the charts. Chicago's worldwide record sales for this single year were a staggering 20 million copies. The group returned with an all-new album in June 1976, when it released Chicago X. (Chicago IX had been a greatest hits collection.) The big hit from the album was a song that just barely made the final cut, Peter Cetera's "If You Leave Me Now." "That was one of those magical 'We need one more song (situations),'" Cetera recalls.

Three months later, Parazaider remembers, "I'm sitting around a pool, and a song comes on, I'm going, 'That's a catchy tune. Where have I heard this before?' The next thing, they go, 'That's Chicago's latest release, "If You Leave Me Now." The main point of the story, outside of me being a dummy, is that often songs that just made the album end up being some of the biggest hits."

"If You Leave Me Now" streaked to Number 1, Chicago's first Billboard singles chart topper. It also topped charts around the world. Chicago X won the band its first platinum record (the awards had only just been inaugurated that year), selling a million copies in three months. Afterward, the ballad style of "If You Leave Me Now" increasingly seemed to become the preferred style of Chicago's audience and radio listeners. "That drove me crazy," says Lamm. "I know it drove Terry crazy, because that isn't what we set out to be and it isn't how we heard ourselves."

By 1977, after eight relentless years of touring and recording, strain was beginning to show. "We'd cut down the touring from 300 dates to 250, down to 200, which is still a lot of days on the road," says Parazaider. "But let's face it, we were booming." In January, Chicago undertook another world tour, and the band was in Europe when they won a Grammy for Best Pop Vocal Performance by a Duo, Group or Chorus for "If You Leave Me Now." They also took Grammys for Best Arrangement Accompanying Vocals and Best Album Cover.

In September, Chicago XI was released, its most notable song being "Take Me Back To Chicago," written by drummer Danny Seraphine and David "Hawk" Wolinski. It has a darker theme than may be immediately apparent. "'Take Me Back To Chicago' is about Freddy Page, the drummer in the Illinois Speed Press who died tragically," says Guercio. Like Chicago, the Speed Press had been brought to L.A. from the Midwest by Guercio in 1968. "Illinois Speed Press had the best shot, had the biggest budget, had the first record, and totally could not get along," he recalls.

The mounting tensions between Chicago and Guercio finally erupted. The split between group and manager had been a long time coming. Guercio had exerted a powerful control over the members of Chicago, especially in the early days, and as they became stars, it probably was inevitable that they would begin to chafe under his harsh leadership. "It started happening with the tenth record," says Parazaider. "He didn't want us to learn any of the production techniques. He'd go to sleep at nine o'clock, and we'd start producing the records ourselves. Or trying to. I think if you're the producer of your album, you have a fool for a client. You can't be that objective about what you're doing on both sides of the glass."

"As I look back, I was much too hard on these guys," Guercio admits. "I felt a thoroughbred by committee is a goddamn mule. I totally manipulated them for my own ends as well as theirs, whether they understood them or not."

In the short term, little seemed changed. "Baby, What A Big Surprise" sailed into the Top 5, and Chicago XI was certified platinum the month after its release. But only a few months later, the band would be devastated by a terrible loss. On January 23, l978, Chicago guitarist and singer Terry Kath died from an accidental gunshot wound. "Terry Kath was a great talent" says Jim Guercio, who worked with him on a solo album that was never completed. "Hendrix idolized him. He was just totally committed to this band, and he could have been a monster (as a solo artist)."

Kath's death devastated Chicago, and the band considered breaking up. "Right about there was probably what I felt was the end of the group," says Peter Cetera. "I think we were a bit scared about going our separate ways, and we decided to give it a go again." A short time after Kath's death, "Take Me Back To Chicago," which by now seemed as much about Kath as about Freddy Page, was released as a single.

If the band was going to continue, it would need a new guitarist, and auditions began in earnest in the spring of 1978. "We felt that we were being left behind by the new music," says Cetera, "and we thought we needed a young guitar player with long hair. We sat through I don't know how many guitar players, but I'm sure it was 30, 40, or 50 guitar players. Toward the end, Donnie Dacus showed up. He played a couple of songs right and with fire, and that's how he was in the group."