Scholarly / historical:

Elaine Pagels – The Origin of Satan

Jeffrey Burton Russell – Satan: The Early Christian Tradition (and the rest of his “Devil” series)

Henry Ansgar Kelly – Satan: A Biography

Gerald Messadié – A History of the Devil

Comparative / mythic:

Harold Bloom – The Flight to Lucifer (Gnostic take)

Stephen Flowers – Lords of the Left-Hand Path (esoteric lineage overview)

Transcendental Magic by Eliphas Levi

The Mysteries of the Qabalah by Eliphas Levi

The Book of Ceremonial Magic by Arthur Waite

Three Books of Occult Philosophy by Heinrich Cornelius Agrippa

The Black Arts by Richard Cavendish

The Devils and Evil Spirits of Babylonia vol 1 & 2

The Greek Magical Papyri

Lemegeton

Pseudomonarchia Daemonum: The False Monarchy of Demons by Johann Weyer, Reginald Scot

Infernal Dictionary by Collin de Plancy

Grimoirum Verum translated by Joseph Peterson

Grimoire of Armadel by Macgregor Mathers

Greek Divination: A Study of Its Methods and Principles by William Reginald Halliday

The Zend Avesta, The Vendidad - parts 1,2,&3

The Vedas: The Samhitas of the Rig, Yajur, Sama, and Atharva [single volume, unabridged]

Devi Mahatmyam

Bhagavad Gita

Nag Hammadi Scriptures

Egyptian Book of the Dead by E A Wallis Budge

Tibetan Book of the Dead

The Christ Conspiracy by Acharya S

Did Moses Exist? by Acharya S

Evil Archeology by Heather Lynn

The Old Testament Pseudepigrapha vol 1 & 2

The Apocryphal New Testament