A diocese will not approve an exorcism until a behavior analyst spends a week in the house. Before the Rite is a spooky parish novel that doubles as a field guide to seeing what a behavior actually buys — attention, escape, a crowd — and what still moves when the paychecks are empty. The bishop’s letter said possible infestation, request behavioral consult. That was the most expensive way anyone had ever asked Mara Quinn, BCBA, to look at a child who growled. The family wants a rite. The priest wants a rite. The clerk wants a file. Mara wants a starting line a camera could catch: growl, low voice, thrown lamp — not possessed, not faking. For seven days she writes what happens before, what happens after, and who is in the room. A neighbor arrives with rolls and a prayer. The voice clocks her in two seconds. Homework hides in a drawer. A mother learns her eyes are a switch. A priest learns that talking to it is a paycheck. Then the house gets quiet on purpose. The talk drops. The crowd leaves. And a bed still changes address without collecting a dime. Before the Rite is two books in one: a fun, spooky original novel about a parish that hires science before it hires the ritual, and a plain-English field guide to applied behavior analysis. After each chapter a Field Card names the principle you just watched — operational definition, audience as a cue, extinction burst, functional communication, treatment integrity — and gives you a small, safe exercise for an ordinary room. Read it if you love The Exorcist and also want to know why the room got louder when everybody came to help. Read it if you work with problem behavior and are tired of stories that skip the data. Read it if you want a child who gets a punchline, a priest who is not a fool, and an analyst who will not chat with the ceiling.