This most unusual book concerns the story of the investigation of a real crime in an English village in 1860, the murder of a 3-year-old boy named Saville Kent, whose body was found at the bottom of an outdoor privy with his throat cut.

The author is London's Kate Summerscale, who also wrote "The Queen of Whale Cay," which won the coveted Somerset Maugham Literary Award.

Summerscale diligently researched the case, based on documents available, including court records, pamphlets and newspapers — even an early book. She visited the former Road Hill House, the scene of the crime, which still stands. She also read many Victorian novels to get the feel of the time period.

In fact, she stuck so closely to the record that some of the narrative gives too much the feeling of being factual, told in legalistic fashion with an excess of detail. Yet, this crime was so well known in its day that it was at least partially responsible for inspiring the detective novel genre.

The real star of this story is Jonathan Whicher, a detective-inspector, sent to investigate the case from Scotland Yard. Whicher was one of the first detectives, as we know the term, in the English-speaking world, and he had a coterie of seven detectives under him. After this case, Charles Dickens wrote about Whicher in magazine articles, and the Whicher character led to fictional detectives such as the tough, quirky Sgt. Cuff in Wilkie Collins' "The Moonstone" and Dashiell Hammett's "Sam Spade."

Whicher used intellectual puzzles to help him solve cases, and so it is easy to see why he was so popular. On the other hand, this Road Hill case was so difficult that Whicher botched it by putting all his efforts into the theory that it was "an inside job" — then being unable to produce the evidence he needed to prove his case.

This was bad for his reputation, but his demeanor and the words he used on the case, hunch, lead, clue and detect, became familiar terms in the culture.

On the other hand, some people thought the police were wrong not to consider an outsider. The "Somerset and Wilts Journal" carried an article suggesting that it was believable that "at least a half dozen persons" could have been "secreted on the premises without risk of detection on that night."

Then the article surprisingly listed in excruciating detail the 19 rooms in the mansion, making it perfect for hiding. "A cellar, divided into six large and small compartments, is entered by two severalseparate doorways and sets of steps. Midway up the back staircase is a large empty cupboard. A spare bedroom over the drawing-room contains a bedstead with valances, a dressing-table with a covering reaching to the ground, and two large and lofty closets, one of which are nearly always empty, and can be locked both inside and out."

Because the case was "the undoing" of the detective, he retired in 1864, at the age of 49, complaining of "congestion of the brain," described as "throbbing headaches, a flushed, swollen face and bloodshot eyes," presumably a result of his work on the Road Hill case. He eventually married, returned to detective work but died at the age of 66 because of stomach problems.

With all the startling twists and turns in the case, it is unlikely that a reader can come close to a resolution of the case until the very end.