Complex sentence: This strip, featuring flapper-era secretary Cam O'Flage, was one of the first daily strips focusing on an independent woman and the first concerned with a group of female office workers.
Split into simpler sentences: This strip, featuring flapper-era secretary Cam O'Flage, was one of the first daily strips focusing on an independent woman. It was the first daily strip to have an "office girl" as the protagonist and to be concerned with a group of female office workers.