This book is full of credible pastiches, told respectfully in the classic manner. As for the style of writing itself: the narration is not bad, but everyone sounds just a bit stilted when they speak -- with Watson coming off the absolute worst, although sometimes both Holmes and Watson give the impression that they just swallowed a technical manual or two. It did not completely get in the way of my enjoyment of the stories, but it is part of the reason for my not giving the book the full five stars. In the originals the style of both writing and speaking was clear and natural.
On a very personal note, the book is a bit heavy on Holmes's drug use for me, but at least his habit is depicted in an extremely unappetizing manner. In one of the stories, Holmes is nodding out so badly that Watson and Mrs. Hudson must lug him to his bedroom, where Watson spends the night trying to bring him out of his drug-induced haze so he will be clear-headed the next morning for an important appointment.
As the book summary states, the majority of the stories revolve around early technologies: telegraphy, flying-machines, a horseless carriage, chemistry, naval weapons and advanced steam engines. I've never had much of a scientific bent, and I freely admit that some of the explanations were a bit technical for me to follow -- but I'm sure plenty of readers will enjoy the detailed mechanical aspects of the stories.
Something the book summary mentioned that I didn't notice much of, is the use of the powers of deduction. But that, it seems to me, is almost always the sticking point with pastiches: stories of pure deductive reasoning do not seem to be that easy for authors of pastiches to write convincingly. The usual "I can tell you came from Sussex because of the color of the dirt on your shoes" doesn't really count as anything original. What counts is that the story should be resolved using inductive or deductive reasoning. A few of these stories depend on guesswork; quite a few more on observation alone. There are 14 individual pastiches in the book.
In "The Railway Van That Vanished," a train car full of gold bullion apparently vanishes mid-trip and an outwardly identical but empty train car is attached when the train arrives at its destination. In "The Brighton Clown," a circus clown is framed for murder by someone wearing the same costume and the police aren't interested in looking past the obvious. "A Liquid Mystery" starts with a client's complaint about untoward noises, unsightly outbuildings, and strange smells coming from the property next door. The mystery liquid features not only in this story, but in several more stories further down the line.
In "The Gong," a man's alibi depends on the difference between railway time vs. local time. My favorite story in the book is "The Tenth Jar," which is a very clever retelling of "The Six Napoleons"...only with marmalade. In "The Deerstalker," Holmes is on the trail of a band of thieves who have stolen an early radar device. "Diamonds at Sea Or The Missing Bridesmaid" is a complex case solved mostly by the Baker Street Irregulars. "The Sycamore Seed" involves crop circles, a flying machine, and a trail of sycamore seeds leading to a kidnapping victim.
"Tracks in the Snow" is about the death of the top expert on the technology of steam engines that could enable Her Majesty's ships to steam halfway around the world without the need to stop to take on more coal. In "Fair Play," Holmes must trick a widow into giving him a very important political document, which when opened, turns out to be in a code that needs to be broken. "The Tiptree Typewriter" sees two seemingly unrelated cases, stolen papers and the kidnapping of a typist, merge together in a most surprising way. In "The Mystery of the Wires," Holmes is tasked with finding out how heavily encrypted, highly confidential information keeps being leaked. In "Not Cricket," a wife is upset by her husband's uncharacteristic and alarming behavior since his return from the war in South Africa and asks Holmes to determine the reason for the change.