The Secret History of Lucifer: And the Meaning of the True Da Vinci Code by Lynn Picknett argues that Lucifer is not the devil, but rather the "Light-bringer" (Venus) representing ancient wisdom, divine femininity, and knowledge, often personified as a goddess. Picknett contends the Christian church demonized this figure to suppress heresy and the sacred feminine, a secret tradition she claims was hidden in the art of Leonardo da Vinci. The book serves as a revisionist history, combining mythological research, Egyptological insights, and art analysis to challenge traditional Christian narratives about good, evil, and the role of women in early Christianity.