This book is set in London in the late 1800's. It focuses on a amateur female detective, Vanessa Duncan, now married with 2 small children. I didn't realize when I got it that it was part of a series, and is actually the third book. Nonetheless, it was easy to follow the actual mystery. A professor, who lived in an apartment above the library, was murdered in his study. Witnesses outside heard a struggle and the shot, but found no one inside. Vanessa must find out who might have murdered the man, who was an ardent anti-Semitic. Was it the mysterious elderly Hasidic man, or someone else. Vanessa is aided by a former pupil and her friends, who are Jewish and give her an inside look into the London Jewish community. The Library Paradox is presented which was an actual logical puzzle proposed by Bertrand Russell. In the end, I figured out the outcome, but the reasoning behind it was interesting. I may go back and get the earlier books in the series.