My dissertation explores the relationship between science fiction (SF)/fantasy and moral discourse in contemporary U.S. fiction. I claim that contemporary literature draws on the SF/fantasy tradition to imagine what a moral life or society could be. In a literary culture where earnest moral commitments can consign a novel to middlebrow perdition, the inclusion of SF/fantasy within a novel's discourse allows ambitious writers to engage morality without suffering the negative aesthetic judgments that straightforward didacticism would incur. SF/fantasy was never elevated to a purely aesthetic sphere, as the modernists attempted to elevate highbrow literature; as such, it never had to distance itself from moral commitment. Moreover, thought experiments are internal to SF/fantasy forms – if aliens invaded earth, then . . . ? – and conducive to moral cogitation. Therefore, when highbrow literature includes SF/fantasy as part of its formal experimentation, moral discourse becomes aesthetically licit for it again. My dissertation analyzes iterations of this dynamic between SF/fantasy and high-literary novels to argue that borrowing from the genre tradition currently serves to enable moral discourse in contemporary U.S. fiction.The dissertation's first chapter analyzes the neo-Kantian rhetoric present in Cormac McCarthy's novel The Road (2006) due to its SF subgenre, post-apocalypticism. The second explores the conflict in Junot Díaz's The Brief Wondrous Life of Oscar Wao (2007) between justified revolution and moral responsibility toward unjust individuals. The third argues that Jeff VanderMeer's Southern Reach trilogy uses SF's penchant for "world building" – modifying our reality or hypothesizing alternate realities – to embed environmental values in the formal representation of features of his imagined world that are very similar to features of our own. His work thus implies that environmental values apply equally to his science fiction and his readers' reality. The fourth analyzes the moral pitfalls of language in Alena Graedon's The Word Exchange (2014).