Never Send an Exorcist to do a Psychiatrist's Job. And the Other Way Round.

In the Spring of 2009, author Matt Baglio published "The Rite: The Making of a Modern Exorcist." Publishers Weekly wrote:

Journalist Baglio follows a Catholic priest through the latter's training to become an exorcist in this incisive look at the church's rite of exorcism and its use in contemporary life. Baglio began delving into the topic after hearing about a course at a Vatican-affiliated university, where he met and befriended the Rev. Gary Thomas, a priest in the diocese of San Jose, Calif. Thomas took the exorcism course at the request of his bishop and subsequently apprenticed himself to a seasoned exorcist. Keenly aware of the misunderstanding that abounds about exorcism through film images, Baglio sets about dispelling misconceptions and does so skillfully, separating the real from the imaginary in the mysterious and unsettling sphere of the demonic. Both Thomas and Baglio were changed by their exposure to the rite. Thomas grew spiritually during the process, which bolstered his desire to help his parishioners, and Baglio, previously a nominal Catholic, reconnected with his faith. For anyone seeking a serious and very human examination of this fascinating subject, one that surpasses the sensational, this is absorbing and enlightening reading.

There is now to be a movie, staring Anthony Hopkins:

In the interest of full disclosure, your author has not the slightest doubt of the existence of personal (unique, individual, identifiable) malevolent spirit beings; that is, demons. The wise will note their existence, be generally wary of their influence, and otherwise pay them no attention. Like poison, their study by the non-expert can lead to no good, and fascination can result in much harm. But -- to carry the analogy further -- we live in a world that doesn't believe in poison, denies its existence, and confidently assures itself that those who do are cranks, mentally impaired, or charlatans. Of course, that same world, at the same time, is dazzled by fictional vampires, werewolves, ghosts, angels, and so on and so forth.

Keep in mind that if you eat rat poison, it will kill you whether you believe in arsenic or not.