Another Sherlock Holmes pastiche from the sainted Nicholas Meyer. Sainted for his involvement with the Star Trek movies. Especially for directing the best one ever.
But his Holmes stuff predates that, the first one (The Seven-Per-Cent Solution) was from 1974 and had Sherlock meeting up with Sigmund Freud, who helped out with his coke habit. (Or something. It's been a long time since I read it.)
The book is set around 1905. Watson is dragged out of his stable marriage to saintly Juliet when Holmes is given an assignment by brother Mycroft: track down the origins of the notorious antisemitic tract The Protocols of the Elders of Zion. A lady spy has been murdered and tossed into the Thames for obtaining a copy in Russian. Can the perpetrators be brought to justice and the vile fraud debunked?
Well, if you know your history: the answer is no.
But they give it their best shot. They get a translation from real-life Russian translator Constance Garnett, and she provides an important clue to the Protocols' plagiarized origin. Holmes and Watson embark on a perilous covert journey to Czarist Russia, where anti-Jewish pogroms are becoming rife. They are accompanied by (again, real-life) activist Anna Strunsky. But the Czar's secret police, the Okhrana seem to be one step ahead of them all the way.
It's not great. There's not a lot of deduction, and Holmes seems to be outmatched, resorting to thuggish tactics to get to the truth. (Doyle wouldn't have done that!) But Meyer has done his homework for the novel's time and place: for example, the trek Holmes, Watson, and Anna take to Russia and back is lovingly described, and I imagine that Meyer dug out just exactly which trains they would have to travel on. (The Orient Express!)