Although somnambulant literary critics have often lumped together the mystery and horror novel, as if each were a subgenre of a larger category, they are, in fact, as mutually exclusive as Rosie O’Donnell and sanity.

The classic detective story is based entirely on observation and deduction, relying solely on reason and granitelike facts to reach its logical conclusion. Supernatural fiction, on the other hand, may draw on fantastic elements to move the plot along for which there are no rational explanations.

When the two literary forms are combined, the sounds you hear are that of horror fans snoring and books being flung against walls by mystery readers. East is east, west is west, etc.

However, it is another accepted truth that rules are made to be broken, to which I would add the caveat that the breaker of the rules should a) know what they are before evading or smashing them, and b) be very skilled.

The finest writer who blurred the lines successfully is William Hjortsberg with “Falling Angel,” though I wouldn’t argue with someone who claimed that first place belongs to Jack Finney for “Time and Again,” in which he made time travel seem utterly believable. Psychic detectives have abounded throughout the history of mystery fiction, mainly in the short story form, and include such memorable characters as Edward D. Hoch’s Simon Ark, who might be 2,000 years old, Randall Garrett’s Lord D’Arcy, who exists in a parallel universe in which the laws of magic apply; and William Hope Hodgson’s Carnacki, the Ghost-Finder, the skeptical detective who often proves that hauntings and ghostly manifestations are man-made.

There is a wonderful new character who somewhat plausibly employs extrasensory abilities to help track down a maniacal serial killer in Jonathan Santlofer’s “Anatomy of Fear” (Morrow, 349 pages, $24.95).

Mr. Santlofer’s first three novels (“The Death Artist,” “Color Blind,” and “The Killing Art”) featured Kate McKinnon, the New York cop who becomes an art historian but is beckoned back by the police to help solve art-related crimes. A major figure in the contemporary art scene himself for a quarter of a century (with works in the permanent collections of many major museums, including the Metropolitan Museum of Art), Mr. Santlofer knows his subject like Ted Williams knew hitting.

Nate Rodriguez is a half-Jewish, half-Puerto Rican sketch artist for the NYPD with an astonishing ability to get witnesses and victims to describe criminals even having had the merest glimpse of them. In his first appearance, several murders are linked when drawings are left with the victims, sketched in the same pose as the actual crime scene.

He becomes attached to the unit charged with hunting down the killer by the attractive and ambitious Terri Russo, to whom Nate also becomes attached. They soon learn that the murderer preys on people involved in mixed racial relationships, a clue that leads them to a variety of neo-Nazi and racial supremacist groups.

Nate’s Puerto Rican grandmother is a santera, a low-level priestess to whom neighbors come for help. She is able to provide this aid with herbs, candles, potions, readings of seashells, and a power to sense danger from places she’s never been and people she’s never met. Nate seems to have inherited this power as well, making it possible for him to visualize and then draw portraits, or parts of faces, of people he has not seen.

The novel is filled with illustrations that juxtapose Mr. Santlofer the artist with Mr. Santlofer the author. Some of them are meant to have been executed by the killer and many by Nate, offering tantalizing clues to the reader.

Mr. Santlofer’s paintings were once described as being concerned with the gap between reality and illusion, and that dichotomy is much in evidence in “Anatomy of Fear,” both in the drawings that richly fill out the text and in the methodology of hunting down the serial murderer.

Where, exactly, is the line between what can be proved and universally shared and that “sixth sense,” for want of a firmer definition, that allows the mind to see things that haven’t yet occurred, or to identify someone never seen before? Mr. Santlofer skillfully makes these wonderful gifts as credible as it is possible for them to be.

What is the best way to say this? There are many people who believe these powers do exist. There are also many people who believe in leprechauns.

Mr. Penzler is the proprietor of the Mysterious Bookshop in Manhattan and the series editor of the annual “Best American Mystery Stories.” He can be reached at ottopenzler@mysteriousbookshop.com.