Chicago is a rock band band that formed in 1967 in Chicago, Illinois. Well known for being one of the first (and, indeed, one of the few) rock bands to make extensive use of horns and for producing a number of hit ballads, Chicago had a steady stream of hits throughout the 1970s and 1980s.
The band was formed when a group of DePaul University music students began playing a series of late-night jams at clubs on and off campus. They added more members, eventually growing to seven players, and went professional as a cover band called The Big Thing. The band featured an unusual and unusually versatile line-up of instrumentalists including saxophonist Walter Parazaider, trombonist James Pankow, and trumpet player Lee Loughnane along with more traditional rock instruments. While gaining some success as a cover band, the group worked on original songs and in 1968 moved to Los Angeles, California under the guidance of their friend and manager James William Guercio, and signed with Columbia Records. Upon release of their first record in early 1969, the band took a new name, Chicago Transit Authority (the name would almost immediately be changed to simply Chicago after the real CTA objected).
The band's first album, the eponymously titled Chicago Transit Authority, was an audacious debut: a sprawling double album (unheard of for a rookie band) that included jazzy instrumentals, extended jams featuring latin percussion, and experimental, feedback-laden guitar abstraction. The album also included a number of pop-rock gems (several of which would later be released as singles and eventually become rock radio staples), and began to receive heavy airplay on the fledgling FM radio band. The band's popularity exploded with the release of their second album, another double-LP set, which included several top-40 hits. The pattern had been set: the band, ever prolific, recorded and released music at a rate of more than two LP discs per year (always titled with the band name and a roman numeral) from their debut in 1969 through the 1970s.
1978 was a tragic and transitional year for the band. The year began with an acrimonius split with long-time manager Guercio and the death of singer and lead guitarist Terry Kath of a self-inflicted gunshot wound. Later in the year the band would release Hot Streets, their first album without Kath and Guercio and their first album with a title rather than a roman numeral (they would return to the old naming scheme immediately afterward). The release also marked a move somewhat away from the jazz-rock direction favored by Kath and towards more pop songs and ballads. This second phase of the band's career lasted through the 1980s with a steady stream of soft-rock hits.