There was one book C.S. Lewis said he didn’t enjoy writing. I know how he felt.

In 1942, Lewis published The Screwtape Letters, which consists of a series of letters from Screwtape, an experienced demon, to his incompetent, inexperienced nephew, Wormwood, who is learning how to tempt people. The book is one of Lewis’s most popular, due in part to the uniqueness of its primary literary device. Instead of writing yet another book on how to avoid temptation, Lewis lets us “peer behind enemy lines” so we see the traps the evil one lays for us and respond accordingly.

In a 1963 interview, Lewis confessed that Screwtape Letters was his least favorite book. He said:

Of all my books, there was only one I did not take pleasure in writing: The Screwtape Letters. They were dry and gritty going. At the time, I was thinking of objections to the Christian life, and decided to put them into the form, “That’s what the devil would say.” But making goods “bad” and bads “good” gets to be fatiguing.

In Devil’s Advocate, I feel a similar strain—but fortunately, I didn’t have to come up with snappy demonic quips. One of the voices is friendly and familiar because he’s me, but the other voice is also friendly (if a bit cheeky) and familiar. That’s what makes him terrifying: he’s the voice of doubt—a real one, voicing real doubts—deep inside me. I suspect most people who will read this book have had conversations with this same sort of person when they finally have some time to be alone with their thoughts. It may even be comforting to know that saints and Doctors of the Church (as well as your friendly neighborhood apologist) have doubts, so there’s nothing wrong with you having them, too.

I hope to share with you how I’ve engaged this persistent adversary. I can’t teach you how to answer your own specific “inner skeptic,” because I’ve never met that person. People are unique, so what might be an insurmountable objection to one person will be just another apologetics trivia question for another. But if I show you as honestly as possible how I handle my own doubts, through a dialogue between myself and my “devil’s advocate,” then hopefully you’ll come away from this book with a rough plan of attack to face the challenges to the Catholic faith that hit you the hardest.

Before you write off the concept of a devil’s advocate, keep in mind that it was the Catholic Church who came up with the term.

The office arose in the Middle Ages as the process of canonizing saints became reserved exclusively to the Holy See. In 1587, Pope Sixtus V established the office of the Promoter of the Faith, whose job was to ensure that candidates for sainthood really had exhibited the holiness others claimed for them and that the miracles attributed to them were authentic. Sixtus’s promoter became popularly known as the advocatus diaboli, the devil’s advocate, who tried to disprove the causes put forward by the advocatus dei, or the “promoter of the cause.”

After the revision of the Code of Canon Law in 1983, Pope St. John Paul II reduced the role of the devil’s advocate, but his essential purpose is still carried out in Vatican investigations of those being beatified or canonized. (In 2003, atheist Christopher Hitchens volunteered to be the devil’s advocate against Mother Teresa’s beatification. That’s . . . not exactly how it works, but points to Hitchens for his enthusiasm.)

The Church saw fit to assign someone the role of attempting to shoot down canonizations to show that seeking strong evidence against your own position isn’t a bad thing. For example, showing that one argument for the Faith isn’t any good may be an opportunity to replace it with a much stronger argument. But that doesn’t mean it’s easy to examine your beliefs in this way. Oftentimes, it can feel like writing dialogue for demons: uncomfortable, unnerving, and even spiritually grimy. But if this can help people see that 1) it is normal to have doubts and 2) there are practical steps we can take to address them and strengthen our faith in the process, then it will be well worth the discomfort.

Order your copy of Devil’s Advocate: Facing my Inner Anti-Catholic today!