Modern society, Michael Trask argues in this incisive and original book, chose to couch class difference in terms of illicit sexuality. Trask demonstrates how sexual science's concept of erotic perversion mediated the writing of both literary figures and social theorists when it came to the innovative and unsettling social arrangements of the early twentieth century. Trask focuses on the James brothers in a critique of pragmatism and anti-immigrant sentiment, shows the influence of behavioral psychology on Gertrude Stein's work, uncovers a sustained reflection on casual labor in Hart Crane's lyric poetry, and traces the identification of working-class Catholics with deviant passions in Willa Cather's fiction. Finally, Trask examines how literary leftists borrowed the antiprostitution rhetoric of Progressive-era reformers to protest the ascendence of consumerism in the 1920s. Viewing class as a restless and unstable category, Trask contends, American modernist writers appropriated sexology's concept of evasive, unmoored desire to account for the seismic shift in social relations during the Progressive era and beyond. Looking closely at the fraught ideological space between real and perceived class differences, "Cruising Modernism discloses there a pervasive representation of sexuality as well.