Since Sherlock Holmes and related characters are all now in the public domain, there is no shortage of non-canon Holmes stories to be found out there, and between the Downey Jr. movies and the modernized BBC series, Holmes' star is currently higher than it has been at any time since the author's death. But the official canon, as written by Arthur Conan Doyle, has remained the same since he wrote the last real Holmes story, The Adventure of Shoscombe Old Place, in 1927.

Until now.

For the first time, the Conan Doyle estate has officially authorized and approved a new addition to the canon. This is The House of Silk, written by Anthony Horowitz (creator and writer of the Foyle's War tv series) and published in November of 2011.

And while this may come as a shock to any Holmes purists, this story is a worthy edition as the fifth full-length Sherlock Holmes novel. It is written credibly in Conan Doyle's style through the voice of Dr. John Watson, and is presented as a mystery so shocking that he was never able to write about it with the others, and kept it secret until his old age, when Watson finally put the story to words and had it put away, only to be opened and published when the people involved were all long dead.

The narrative voice is authentic, which is good for fans but not as good for those who find the Victorian tone and style of the Holmes stories too stodgy and old-fashioned. There has been no modernization here. But if you can stand the old-fashioned presentation, the book is a quick read at only 300 pages and presents an interesting, engaging, and thoroughly believable new set of mysteries for Sherlock Holmes to solve.

The book opens in 1890, one year before Holmes' original fake death at the hands of Professor Moriarty. The original detective duo set out to solve the mystery of a man in a flat cap who appears to be stalking a well-to-do art dealer because of events that occurred in America the year previous. Holmes being who he is, he unravels most of the details in relatively short order, but before he can polish off the case and make one of his famous revelations, everything goes to hell.

The case suddenly morphs into a whole new mystery, as Holmes and Watson are drawn into the circumstances of the brutal torture and murder of a child. As Holmes works to untangle an increasingly complicated web, he begins to work out the existence of a horrible and wide-ranging conspiracy throughout the power structures of Victorian London, known only as the House of Silk. Facing murderous thugs, desperate and dangerous villains, and then with Holmes himself framed lock stock and barrel for murder, the great detective will have to call upon all of his fabled wit and observational intelligence to clear his name, unravel the conspiracy, and save the unwanted children of London in a case that could bring the entire upper echelons of Victorian society crashing down.

The novel brings back all of the old favourites, including Mrs. Hudson, Lestrade, the Baker Street Irregulars, Mycroft Holmes, and even a cameo appearance by Professor Moriarty a year before his famous clash with Holmes, while at the same time introducing a wide range of new characters threading in and out of the narrative.

One of the best parts of The House of Silk is that, unlike some of the original Holmes stories, it is entirely possible for the reader to work out the mysteries if he or she is observant and clever enough. The story's two main mysteries and a handful of smaller puzzles are all presented with enough clues to unravel if you can think things through the same way Holmes would.

Did I manage to work them out, you ask? I figured out the majority of one of the two major mysteries, and got the gist of the biggest of the smaller puzzles, but was unable to figure out the other main mystery. It was fun.

One possible drawback is that every now and then the author appears to lose the authentic Watson voice in order to insert more contemporary judgements of Victorian society, or to ruminate about why the original Conan Doyle-penned Watson never gave much attention to side-characters such as Mrs. Hudson and Lestrade. This is presented as older Watson thinking back about his old stories and what he left out of them, but it feels like the author injecting his own pet peeves into the narrative.

But on the whole, The House of Silk is a capable, interesting mystery novel and an authentic, worthy addition to the Sherlock Holmes canon. If I were to copy Werthead's scoring system, I would give it **** and a half out of five, and wholeheartedly recommend it to anyone who has enjoyed Holmes stories in the past.