Since the dawn of civilization, humanity has confronted invisible forces, both beneficial and malevolent, that have shaped its beliefs and understanding of the cosmos. Demonology and the History of the Devil undertakes an ambitious archaeological exploration of evil spirits, revealing how primitive deities were gradually degraded into demons and devils, central characters in the mythology and folklore of various cultures. This study — one of the most comprehensive and scholarly works written on the conception of Evil in our civilization — tracks the evolution of the dualism between Light and Darkness, from the earliest personifications of natural phenomena to the complex figure of the Devil. It examines the various manifestations of evil: from the demons of hunger, heat, or disease, to fearsome serpents and dragons, and finally, the theological Adversary. The work analyzes the ethnic, climatic, and political circumstances that shaped these conceptions, illustrating how human fear and need materialized into a vast progeny of supernatural beings. Moncure Daniel Conway unravels the intricate web of superstitions, revealing the origins and persistence of demonic beliefs. His comparative analysis of mythologies, from the Rig-Veda to the Koran, illuminates the surprising continuity of certain ideas and the adaptability of archetypes of evil. The result is a work that not only documents a vast tradition, but also invites reflection on the profound interaction between the human mind, nature, and the construction of morality.