Start with high-confidence demonology & satanism books, then narrow by subgenre or adjacent topics.
Hostage to the Devil - Reissue
Malachi Martin
The Kingdom of the Occult
Walter Martin, Jill Martin Rische
Sense and Nonsense About Angels and Demons
Kenneth D. Boa, Robert M. Bowman Jr.
Satan Is Alive and Well on Planet Earth
Hal Lindsey, Carole C. Carlson
Satanic Bible
Anton Szandor Lavey, Peter H. Gilmore
Oedipus and the Devil
Lyndal Roper
The Discoverie of Witchcraft
Reginald Scot
The Prince of Darkness
Jeffrey Burton Russell
Satan
Lucifer
Mephistopheles
Angels and Demons
Serge-Thomas Bonino OP, Michael J Miller
The Day Satan Called
Bill Scott
Reviving Old Scratch
Richard Beck
Demons
Michael S. Heiser
