Sullivan acknowledges that the idea of Satan as an opponent of God and a purely evil figure only seems to energe during the Second Temple Period Judaism, probably due to Zoroastrian dualistic concepts such as Ahriman, particularly in the apocalypses.

He references major literary, religious and historical figures, Zoroaster, Plato, Augustine, Thomas Aquinas, Martin Luther, John Milton, and many more, among them Charles Baudelaire, from whose work Sullivan took the title of the book.

Witch hunts in Europe in the 15th and 16th centuries reached a climax in England in the 17th, when a professional “witchfinder” named Matthew Hopkins managed to execute some 300 women over a two-year period in the 1640s.

In a positive review for The New York Times, Clancy Martin describes the book as a "master class in the difficult art of first-person, narrative nonfiction".

Micah Mattix of The Wall Street Journal gave a mostly positive review, writing: "Mr. Sullivan is a gifted storyteller, even if the shifts between recent events and intellectual history can be jarring."

"[2] A negative review from Carl Hoffman in The Washington Post criticized the book as "one big, sloppy mess that is written strictly from the perspective of the minority of humankind who call themselves Christians".