The fourth season of The Simpsons echoes much of the strength of the previous season, while further building on the formula that represented the golden years. The greatest advance in this season compared to previous is the greater incorporation of music, especially prominent in "A Streetcar Named Marge" and "Marge vs. the Monorail." The Treehouse of Horror episodes remain a highlight, and the retrospective explores Bart and Lisa's relationship, nearly as central as that of Marge and Homer. Homer begins his long litany of jobs, as he is a union boss and snow plow diver, while Marge's role is expanded as she stars in a musical and works with Homer at the nuclear plant. The season saw the first clip show in the series, but thankfully bundles it in a more substantial frame narrative. Springfield itself is developed the most in the season, as the strangeness of the town is featured especially in "Whacking Day" and "Marge vs. the Monorail." While satire and cultural commentary have been present from the beginning, religion as a frequent target becomes more prominent in "Homer the Heretic." ( )