Touchstone by Laurie King

I really had to work to finish reading this book.  The touchstone the book refers to is Bennett Grey, a WWI veteran who was wounded in the trenches.  As a result of his injuries, Grey is able to discern whether a person is truthful, often by a strong visceral reaction to deception of any kind. Unfortunately, Grey is not the main character.  Laurie King felt the need to anchor the story on the shoulders of an American FBI agent on holiday.  Harris Stuyvesant is using his personal time to track an anarchist bomber back to England.  His search leads him to a shady character named Carstairs who is looking for a way to coerce Bennett Grey into assisting him with his "research" on lie detectors and the efficacy of torture.  Carstairs points Stuyvesant to Grey, or rather Grey's sister, as a way to get into the Anarchist circle.  As you might imagine, you have to read a lot of backstory to keep up with this plot. History buffs interested in a light version of the labor troubles in the U.S. and England pre- and post-WWI might find this story engaging but other folks will probably want to give it a pass. 548 pages.