What Dreams May Come in the book are derived from my wide range of reading." One of Matheson's influences was Harold W. Percival, an adherent of Theosophy, a belief system with a strong Eastern and Hindu influence. The story also shares the same theme of the ancient Greek myth Orpheus and Eurydice, in which the gifted musician makes a challenging journey to Hell to retrieve his wife. One character quotes from the writings of 18th century Christian mystic Emanuel Swedenborg. Matheson bases his descriptions of the death experience itself on studies by Elisabeth Kübler-Ross and Raymond Moody. When reading these accounts, Matheson found that
Hades More elaborate names of the same genre were "Ploutodótēs" () or "Ploutodotḗr" (), meaning "giver of wealth". Epithets of Hades include "Agesander" () and "Agesilaos" (), both from "ágō" (, "lead", "carry" or "fetch") and "anḗr" (, "man") or "laos" (, "men" or "people"), describing Hades as the god who carries away all. Nicander uses the form "Hegesilaus" (). He was also referred to as "Zeus katachthonios" (Ζεὺς καταχθόνιος), meaning "the Zeus of the Underworld", by those avoiding his actual name, as he had complete control over the Underworld. In Greek mythology, Hades, the god of the underworld, was the