During the investigation of poltergeist (or poltergeist-like) activity, it is usually discovered that the sounds, movements, etc. are centered around one person, most often an adolescent female. Such an individual is known as a focal person.
Readers, please enjoy this guest blog post by Sandra Kynes, author of several books, including The Herb Gardener's Essential Guide, Plant Magic, and the new Witches' Encyclopedia of Magical Plants, among many others.
Although a few old books...