The debates of Dr. Louis Leakey, Desmond Morris, and Robert Ardrey influence not only the first section but the broad themes of the novel. The use Clarke and Kubrick made of the Odyssey in structuring the screenplay and novel is clear, and the Divine Comedy plays a part in the afterlife pilgrimage of Bowman; and Stapledon, in Last and First Men, remains important. But the major background to the novel is Clarke's own work; as several commentators have noted, narrative motifs have been woven into it from "The Sentinel," "Transcience," "Encounter at Dawn," "Out of the Sun," "The Possessed," and his moon novels.