Magdalene Myserties: The Left-hand Path of the Feminine Christ by Seren Bertrand and Azra Bertrand is a deep dive into Mary Magdalene, viewing her from Biblical, historical, and mystical perspectives.
In The Spiritual Roots of the Tarot: The Cathar Code Hidden in the Cards, author Russell A. Sturgess presents the story of a medieval group of Gnostic Christians who are later referred to as the Cathars.
Ancestral Tarot: Uncover Your Past and Chart Your Future by Nancy Hendrickson immediately drew my attention because it combined two interests of mine: tarot and ancestry.