In his work, “On Fairy Stories,” J. R. R. Tolkien offers a detailed account of what he calls Sub-creation, along with the corresponding notions of Primary and Secondary Worlds. In this paper, I suggest that Tolkien’s concept of Sub-creation can be creatively appropriated in the realm of moral psychology and there applied to the fundamental relationship between self and other – or in Judeo-Christian terms, “I” and my neighbor. Through appeal to Tolkien’s thought and to the wider Christian theological tradition, and in constructive tension with the contemporary psychoanalytic attention to “intersubjectivity,” I attempt to elucidate the power and appropriate function of the human imagination to dispose us to good moral action, and so to bring us closer to ultimate happiness