In July 1970, Chicago was riding high on the success of their second album, "Chicago," also known as "Chicago II," which had been released in January of that year. This album featured hits like "25 or 6 to 4" and "Make Me Smile," solidifying the band's presence in the rock and jazz fusion scenes. The live recording of "I'm a Man" from Tanglewood showcases the band's energetic performance style during a time when they were transitioning from an innovative pop band to a major rock act. It's notable that this performance featured Terry Kath's impressive guitar work and Robert Lamm’s lead vocals, emphasizing the band’s talented lineup. This era was pivotal for Chicago, as their incorporation of horns and varied musical elements began to set them apart and contributed to their distinctive sound, helping them develop a dedicated fan base.