What is the author's purpose in the novel, Night of Light?

Night of Light is not primarily a "social" novel, but a philosophical or allegorical one. As the two opposites of the title foreshadow, Farmer attempts to reconcile the eternal dualities of life: darkness and light, good and evil, reason and madness, permanence and change. Because the novel ends in a stand-off between Yess and his evil twin, Algul, these dualities are shown to be not the complete opposites of Western thinking, but complementary opposites, essential elements in the fundamental composition of the universe.