The Biography of Satan is a book by Kersey Graves, first published in 1879. In this provocative work, Graves explores the historical, mythological, and theological origins of the figure known as Satan, arguing that the concept evolved through the interplay of ancient mythologies, cultural superstition, and ecclesiastical authority. Drawing on comparative religion and early history, he presents Satan not as an independent supernatural being, but as a construct shaped by religious power and fear. Graves places the blame for the persistence of the Devil myth squarely on the institutions that benefited from maintaining belief in eternal punishment and moral dualism. This work reflects the 19th-century freethought movement's skepticism toward orthodox Christianity, particularly its more fear-based doctrines. As with his better-known book The World's Sixteen Crucified Saviors, Graves challenges traditional dogma and urges readers to question inherited beliefs. The book remains a bold and controversial critique of religious literalism, appealing to readers interested in the intersection of mythology, philosophy, and historical inquiry.