Final answer:
Sinclair Lewis's novels often revolved around his critical perception of society, particularly the American middle class, which he viewed as shallow and conformist. His intent was to provoke thought and encourage reform, earning him a Nobel Prize in Literature.
Step-by-step explanation:
A principal theme of Sinclair Lewis's novels was his critical view of society, particularly American middle-class society. His works, including Main Street and Babbitt, represented his highly critical views, portraying middle-class life as stifling and shallow.
In Babbitt, Lewis examines what he perceived as the 'sheep following the herd' mentality and satirized the mindless pleasure-seeking of American life. Sinclair Lewis was deeply influenced by Progressivism, and his writing did not merely express disillusionment, it showed a progressive critique of social norms and was aimed at provoking thought and potential reform among his readers. He won the Nobel Prize in Literature for his vivid depictions of American life.