This dissertation examines how Octavia Butler revises such speculative fiction generic conventions as the alien encounter, space exploration and colonization, utopia/dystopia, and time travel. I argue that Butler borrows heavily from classic science fiction, feminist utopia, and African American literature. In so doing, Butler both expands and critiques these genres, discarding elements that she finds limiting, and reshaping those that she finds valuable. Although Butler’s contributions to both speculative fiction and African American literature are many, among her most notable achievement is the reconfiguration of heroic power. Butler creates scenarios in which young black women, many of whom are mothers, and many of whom possess either physical or mental illnesses, find themselves “chosen” to lead in all manner of future worlds. While Butler does not suggest that there is anything essential in black female motherhood that equips her heroines to lead, their histories on the margins—centuries of psychological and physical violation—uniquely equip Butler’s heroines to thrive. Because of the compromises they have always been forced to make in order to survive, Butler’s protagonists are able to serve as messianic figures who serve as bridges between past, present, and future. Furthermore, Butler’s protagonists rely heavily upon their communities (while also being reluctant mothers), negotiate rather than demand, and collaborate rather than dominate. Additionally, Butler’s heroines are receptive to radical change even when that change comes at the partial loss of humanity. Because they have less of a stake in the world as it exists, Butlerian heroines are in ideal positions to usher in the unthinkable realities of Blochian utopian dreaming, envision new social organizing principles, and embrace initially destabilizing but ultimately beneficial forms of embodiment that problematize identitarian categories.