[13] Their trademark was fusing brass and jazz with a soulful rock and roll feel that Guercio thought would prove successful, lobbying for his label to sign the band.

[17][18] In addition to the material recorded for the album, "Wake Up Sunshine", "It Better End Soon" (both later released on their second album), "Loneliness is Just a Word" (later released on Chicago III), and an early version of "Mississippi Delta City Blues" (with mostly different music than its eventual versions on Live in Japan and Chicago XI) all date from this era, and were performed as early as 1968.

[19] Released in April 1969, Chicago Transit Authority (sometimes informally referred to simply as "CTA") was not an immediate hit, eventually reaching No.

[21] While critical reaction was generally favorable, sales were slow at first and the album initially failed to produce any hit singles, with the group seen as an album-oriented collective.

Buoyed by the success of their later albums, Chicago Transit Authority had stayed on the charts for 171 weeks as of June 1975,[8] setting the then record for a rock album's chart longevity by October 1974 at 155 weeks,[9] and was certified gold (and later platinum and double platinum) by the Recording Industry Association of America (RIAA).

[24] Keyboardist Robert Lamm, guitarist Terry Kath and bassist Peter Cetera shared lead vocals, while James Pankow, Lee Loughnane and Walter Parazaider handled all brass and woodwinds (trombone, trumpet and saxophone, clarinet and flute respectively)[a] and Danny Seraphine played drums.

According to the band's producer, James William Guercio, Jimi Hendrix was an avowed fan of Kath's playing.

[26][18] According to the album's original liner notes, the solo performance of Kath on "Free Form Guitar" was created without the use of any pedals.

[citation needed] In 2010, Rhino Handmade re-released the original quadraphonic mix of the album on a limited edition DTS DVD,[33] and in 2016, in DTS-HD Master Audio, as part of Chicago Quadio Box Set.

[34] On June 26, 2019, Rhino Records announced a 50th Anniversary Remix edition of Chicago Transit Authority, offering it in both CD and double LP formats.

"[37] In his review for All About Jazz, Doug Colette gave the CD four out of five stars, noting that there's "less precedence for the harmony singing," but that there's "wallop to the drums," "edge to the guitar," and "great care throughout to highlight, without overstatement but with proportionate accuracy and impact, the tightly-fused rhythm work of drummer Danny Seraphine and bassist Peter Cetera: both sound equally vigorous and muscular in their playing.