When I first saw Chicago, live, they were Chicago Transit Authority.
Their first record (released in April 1969), the eponymous The Chicago Transit Authority, was an audacious debut: a sprawling double album, virtually unheard of for a rookie band (only "Freak Out!" by The Mothers of Invention and "Loosen Up Naturally" by Sons of Champlin, featuring Bill Champlin, who would later become a member of Chicago, preceded it) that included jazzy instrumentals, extended jams featuring Latin percussion, and experimental, feedback-laden guitar abstraction. The album began to receive heavy airplay on the newly popular FM radio band; it included a number of pop-rock gems — "Does Anybody Really Know What Time It Is?", "Beginnings", and "Questions 67 and 68" — which would later be edited to a radio-friendly length, released as singles, and eventually become rock radio staples.When I first saw the band, in 1970, Chicago was the opening act for Edwin Starr, who was topping the charts at the time with War.
Soon after the album's release, the band's name was shortened to simply Chicago, when the actual Chicago Transit Authority threatened legal action.
In 2009, Chicago will reunite with Earth, Wind and Fire for yet another joint tour, which is scheduled to arrive in Chicagoland on June 26th, so I may have to come back.