My reviewRating: 3 of 5 stars
Not a super-complicated mystery (I think of this series as similar to "The Closer" TV show: if something or someone pops up for no discernible reason, that means it's a clue to the killer). Nevertheless, there were several interesting passages detailing the birth of automatic handguns. This builds upon the authors' previous examinations of modern technology (including motor cars and forensic techniques) as it developed at the end of the Victorian Era. This aspect remains one of the most unique parts of this mystery series.
Also, the use of quotations from totally random sources abates somewhat relative to previous entries in this series. However, it doesn't go fully away.