<p>By the 20th century, the centuries-old Roman Catholic exorcism ritual for combatting demonic possession was all but dead, eviscerated by the ascent of modern science and rationalism. But Ray Russell''s 1962 novel, <i>The Case Against Satan</i>, set the stage for a proliferation of exorcisms on page, screen, and even bizarrely, in real life.<br><br>Just a few weeks ago, Susan Garth was "a very good girl, a clean-talking sweet little girl" of high school age. But that was before she started having "fits"-a sudden aversion to churches and a newfound fondness for vulgarity. If not madness, then the answer must be demonic possession, for which there is only one response: exorcism.</p>