In January 1969, when the group flew to New York to begin work on its first album, it faced two problems it knew nothing about. The first was that, because the Guercio-produced Blood, Sweat and Tears LP at first appeared to be a flop (though it later became a spectacular hit), the status of his new project, CTA, suffered: The label curtailed the amount of time the band would have in the CBS studio. The group was allowed only five days of basic tracking and five days of overdubbing. And then there was the second problem. Although they were well rehearsed, the band members had never been in a studio before.

"We actually went in and started making Chicago Transit Authority and found out we knew very little about what we were doing," says Walt Parazaider. "I had done commercial jingles in Chicago, but this was a totally different thing for all of us. The first song was "Does Anybody Really Know What Tine It Is?" We tried to record it as a band, live, all of us in the studio at once. How the hell do you get seven guys playing it right the first time? I just remember standing in the middle of that room. I didn't want to look at anybody else for fear I'd throw them off and myself, too. That's how crazy it got. I think that we actually realized after we didn't get anything going that it had to be rhythm section first, then the horns, and that's basically how we recorded a lot of the albums."

But after they worked out the basic mechanics of recording, the large bulk of material the band had amassed began to be a problem to fit on the then standard 35-minute, one-disc LP. The band had more than enough material for a double album, and they wanted to make a statement.

If they had lot to say, this seemed like the time to say it. Early 1969 was a period when rock was taking on a seriousness undreamed of only a few years before. The Beatles had recently released their two-record "white" album and had also shattered the previously sacrosanct three-minute limit for a single by spending over seven minutes singing "Hey Jude."

When told of the band's intention to make a double album, Columbia's business people informed Guercio that CTA could have a double album only if they agreed to cut their royalties. The band agreed.

Chicago Transit Authority is a time capsule of the popular musical styles of the late '60's, with CTA's own unique flavor on top. One can pick out the group's classical, jazz, R&B, and pop influences, bearing references to Beatles as well as Jimi Hendrix. One can hear the band's own history: Kath's "Introduction," which does in fact introduce the band in confessional form ("We're a little nervous"), is CTA's own version of the kind of funky bar band rave-up of Sly and the Family Stone's "Dance To The Music" or Archie Bell and the Drells' "Tighten Up." Midsong, one moves from the bar to the lounge for some lovely horn playing, and moments later one is in a concert hall listening to a screaming rock guitar solo by Kath.

And so it goes, "Does Anybody Really Know What Time It Is?" starts with an acoustic piano that is equal parts Erik Satie and Art Tatum, while the song itself is a bright, pop melody contrasted with a typically anti-establishment lyric. "Questions 67 And 68" combines a stately horn chart with some hot guitar and a musical cadence reminiscent of pop songs such as Jimmy Webb's "MacArthur Park." All through, there are the inventive horn charts, the sophisticated rhythm changes and startling musical juxtapositions, the alternating smooth (Lamm), soaring (Cetera), and soulful (Kath) singing that would become hallmarks of the classic Chicago sound.

Released in April 1969, Chicago Transit Authority was played by the newly powerful FM album rock stations, especially college radio. "AM radio wouldn't touch us because we were unpackageable," says Pankow. "They weren't able to pigeonhole our music. It was too different, and the cuts on the albums were so long that they really weren't tailored for radio play unless they were edited, and we didn't know anything about editing. Actually, we released three singles off the first album. We edited three songs and released them, but AM radio was nowhere near ready for this kind of music, The album was an underground hit, FM radio was embraced by the college audiences in the late '60's. All of a sudden, the college campuses around the country discovered Chicago, and it was over. That was the beginning of the snowball. If you didn't listen to Chicago, you weren't hip. It was the college kids and word of mouth that made that album such an incredible, enormous mainstay on the pop charts."

The album broke into Billboard magazine's Top LP's chart for the week ending May 17, 1969, and eventually peaked at Number 17. By the end of 1972, it had amassed 148 weeks on the chart (and that wasn't the end of its total run), making it the longest running album by a rock group up to that time.