PHOTOGRAPHING FAIRIES By Steve Szilagyi Ballantine. 321 pp. $18

AS IF BY magic, author Steve Szilagyi -- in a startling imaginative leap -- induces readers to suspend their disbelief just enough to accept the existence of (yep!) fairies -- at least within the pages of his arrestingly original debut novel, Photographing Fairies. Written in an overly genteel Edwardian prose style, Szilagyi's story is set in 1920s England where 32-year-old American portrait photographer Charles Castle awaits his hanging on the next day for a murder he did not commit. Testing the truth of Samuel Johnson's witticism that "when a man knows he is to be hanged in a fortnight, it concentrates his mind wonderfully," the extremely self-conscious Castle proceeds to narrate an astonishing tale of the events leading up to his present gloomy situation.

Only four months before, he tells us, while working in his London photography studio, he was accosted by a brutish country policeman, Constable Michael Walsmear, who literally punched his fist through Castle's darkroom wall. Walsmear has come to Castle on a unique personal matter: to verify the authenticity of two photographs that, Walsmear maintains, depict fairies. At first, all Castle sees in the "fairy photos" are two lovely, innocent girls standing in a beautiful garden. He also notices that "both shots were marred by small, bright splotches here and there around the girls' figures." When Castle later enlarges one of these splotches, however, he begins to perceive in it "a female figure . . . less than ten inches tall!"

Reeling from his discovery, Castle, after returning the photos to Walsmear, decides to take his enlargement to be examined by the eccentric Sir Arthur Conan Doyle who, besides being the renowned author of the Sherlock Holmes detective stories, is also a publicly avowed spiritualist, parapsychologist and dabbler in the supernatural. Locating Doyle in his occult bookshop, Castle discovers that Doyle is not only interested in Walsmear's fairy photographs, but possesses a collection of his own which Doyle considers the linchpin in his campaign to make the world a kinder, gentler place by making it believe in fairies. To Castle, however, Doyle's collection appears laughably fake, the fairy figures merely painted onto the photographs.

At this point Doyle, fearing his leadership in his fairy campaign is threatened, offers L1,000 to Castle to destroy all of Walsmear's photographs. Castle accepts, and his quest to find the photos takes him to the peaceful, rural village of Burkinwell, where Walsmear and the two ethereally beautiful young girls live, and where the fairy garden is located.

In Burkinwell, Castle meets a truly odd assortment of characters. There is the attractive Linda Drain, wife of the town's minister, who often lies on pillows reading magazines in front of the church altar when no services are being held, and who frequently zips off to London to partake of the feverish jazz nightclub scene. There is the Rev. Drain, who by day jogs around the village to the point of red-faced exhaustion, and by night writhes naked in the magic garden while invisible fairies dance on his body thereby bringing him to a sexual frenzy. There is Esmirelda, the shallow, sexually suggestive serving woman at the Starry Night Inn where Castle takes up residence. And there is the secretive and syphilitic Brian Templeton, father of the two young girls, Anna and Clara, and owner of the fairy garden. Other elements of the plot consist of two murderous burglars and a nearby camp of orgiastic gypsies.

In the midst of his mission to obtain the photographs, a greedy idea occurs to Castle: If he can take his own photos of the fairies, thereby proving their existence, and if he can enlist the necessary partnership of Walsmear and Templeton, then "the possibilities are endless. The demand for anything having to do with fairies will be enormous . . . moving pictures . . . books, postcards, you name it. Burkinwell will become the greatest tourist attraction in the world." TO GIVE away any more of the story or to describe Castle's wondrous encounters with the fairies would be a great disservice to the reader. Suffice it to say that it is a tribute to Szilagyi's tight literary control that his portrayals of the supernatural are not only convincing but enthralling as well.

Szilagyi's descriptions of the natural world, too, are breathtaking. His lush renderings of English gardens filled with "waving trees . . . jets of blossoms . . . exploded sprays of pink and lavender, blue and yellow, amid petal textures of velvet, crepe, flesh and japan" are exquisite.

Besides relating a delightful and tantalizing journey into the fantastic, this novel vibrates with the tension of a topnotch detective story. It is also a sobering lesson about how corruption can co-exist with the sublime. Mesmerizing and offbeat, Photographing Fairies is an irresistible treat.

Chris Patsilelis has reviewed for the Philadelphia Inquirer, the San Francisco Chronicle and the Hartford Courant.