Originally the Chicago Transit Authority, before running afoul of Mayor Daley's lawyers, they were a soul/hard rock band with a jazzy horn section. They pushed the envelope with inventive arrangements and semi-ambitious lyrics. As the years passed, they ditched much of the complexity, and the lyrics became vapid or cringe-inducing - they turned into massively successful Top 40 "superstars", with a Dick Clark-produced TV special and everything. Now playing all the hits, on the Rock Senior Tour.