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
Orpheus son of the Thracian king Oeagrus and the Muse Calliope. Greeks of the Classical age venerated Orpheus as the greatest of all poets and musicians; it was said that while Hermes had invented the lyre, Orpheus had perfected it. Poets such as Simonides of Ceos said that Orpheus' music and singing could charm the birds, fish and wild beasts, coax the trees and rocks into dance, and divert the course of rivers. Orpheus was one of the handful of Greek heroes to visit the Underworld and return; his music and song even had power over Hades. Some sources credit Orpheus