Written by Robert Lamm for the group Chicago, 25 Or 6 To 4 appears on their second album Chicago released in 1970. 25 Or 6 To 4 was further edited and released as a single later that same year, climbing to number 4 on the Billboard Top Forty.

Written by Peter Cetera, Baby What A Big Surprise was released on Chicago XI. Baby What A Big Surprise was the first single released from the Chicago XI album reaching number 4 on the Top Forty. Carl Wilson additionally provides backup vocals on the released version.

Colour My World was a single released from the group Chicago (Transit Authority) and appears on their second studio album Chicago II, 1970.

Released from the Chicago album XVI (16), Hard To Say I’m Sorry is another composition written by Peter Cetera and David Foster for the group Chicago. Released in 1982, Hard To Say I’m Sorry went to number one on the Billboard list for two weeks with a slow decline in popularity.

Chicago released the song If You Leave Me Now from the album Chicago X in 1973. Another Chicago hit using the now familiar style of slow ballad-rock music. If You Leave Me Now was written by Chicago member Peter Cetera. Upon the release of If You Leave Me Now the song reached the number 1 position and stayed there for a number of weeks.

Saturday In The Park was recorded for the group Chicago and released on the album Chicago V. Written by Robert Lamm in 1972, Saturday In The Park became Chicago‘s highest charting single to date. According to fellow Chicago band member, Saturday In The Park was written by Robert after spending a Saturday afternoon (Fourth of July) in New York.

You’re The Inspiration is a slow rock ballad written by Peter Cetera and David Foster and was recorded by the group Chicago. You’re The Inspiration appears on the Chicago 17 album released in 1984. The third single released from the Chicago 17 album the song went to number three on the Billboard.