annaloog: For what it's worth, according to Wikipedia "By the end of the Chicago Transit Authority sessions, the band had decided they wanted it to be a double album. Skeptical, as the band had no track record, Columbia agreed to the concept only if the group would take a royalty cut.".
They were quite productive, as in addition to the album, at least six other songs were done during the sessions including "Wake Up Sunshine".
Had this originally been planned as two single disk albums? I note the disparity between the two disk numbers, CS 9809 and CS 9836, and the two sets of matrix numbers.
Produced by James William Guercio
Recorded at Caribou Ranch, Nederland, Colorado
Engineered by Wayne Tarnowski, Jeff Guercio, Mark Guercio
Mixed by Phil Ramone