When it is OK for a 65-year-old man and a 16-year-old girl to have a romantic relationship? Most of us who've been around a few decades would say, Never. It speaks to Joyce Carol Oates' stealthy genius that halfway through "Fair Maiden," we're almost convinced that the deepening relationship between Katya Spivak, a pretty teenager who dreams of escaping from her abusive, impoverished New Jersey family, and Marcus Kidder, an elegant, wealthy artist and writer, is not just OK, but good for both of them. Ah, but we're fooled -- though just how is not easy to predict.

"Fair Maiden" is full of creepy, memorable moments, as when Marcus plays Katya a scratchy old recording of a much younger himself singing "Barbara Allen," reducing her to troubled tears.

"Fair Maiden" is one of the brilliant and prolific Oates' minor works -- that is, "just" a mystery -- but like all very good mysteries, it's also a psychological study. In the tradition of Edgar Allan Poe, Oates' Gothic-tinged mysteries begin with bright hope that is chipped away and replaced by foreboding, then shock, as violence erupts and creepy truths emerge.

Is Katya victim or abuser? Is Marcus predator or prey? The answers are not simple or predictable, but they certainly add up to one arresting story.

PAMELA MILLER