This story, never told before, is based on true events.
David had created an extremely entertaining novel that nicely blends fact and fiction. The first chapters of the book dramatize Houdini's tour of Russia quite accurately, including his performances at Establishment Yard and his famous escape from the Siberian Transport Prison Van (David elects to go with the sawing through the floor method). The book then heads into it's fictional narrative when Harry and Bess join the Russian Royal Court and move into the Royal Palace, and President Roosevelt seeks to make the Handcuff King his own secret agent. Lots of intrigue and Master Mystery-like escape action ensues, with Harry finding himself in dungeon chains and even a Spanish Maiden.
Throughout the book David interjects accurate details about Houdini's life and character. He even includes a nod to his possible claustrophobia. And unlike other recent Houdini spy fiction, David keeps Houdini's activities more rooted in his character and profession -- his primary "assignment" being to expose the (real-life) medium Philippe, who appears to be driving the superstitious Tsar into war. Houdini even uses the name Heath Haldane at one point!
David also nicely parallels the backstory of Mayer Samuel, Houdini's father, whose own encounter with royalty led to him fleeing his home country. Bess and Franz Kukol also play large parts in the story, as do characters out of history such as Gorky and Chekhov.
In his afterward, David pegs his novel at being 98% factual. I'm not sure I'd place the number that high (for starters, Bess is blonde), but I'll leave it to the reader to formulate your own percentage, and also enjoy a darn good piece of Houdini fiction while you're at it.
HOUDINI UNBOUND: Espionage in Russia can be purchased as a hardcover, paperback and eBook from at Amazon.com (U.S.) and Amazon.co.uk (UK).