The theme of Main Street is portrayal in detail of the mediocrity of the American small town and the narrow-mindedness and lack of vision of its inhabitants.
The plot is rambling and episodic. The first three-fourths of the book deals with Carol's rebellion against Gopher Prairie and its inhabitants. In the last fourth, her battle is with her husband and the ideas he represents.
Mark Schorer says that Main Street follows the pattern of Lewis' earlier novels. A young person finds herself in "a stultifying environment, tries to reform and then break out of that environment, succeeds for a time, and then makes a necessary compromise with it." The difference is that Main Street is "predominantly satirical."
Each chapter of Main Street is divided into several sub-sections. Hence the book is well adapted for "pick-up" reading.