I picked this up as one of the few books, other than straight romance novels, that I could find at the library set in early nineteenth century England/Regency period. I found the book started off a little slow, especially as I got used to a more distant writing style/POV than I am used to, but it picked up and proved to be a fascinating might-have-been involving a French plot, Bow Street Runners and early submarine warfare. The details of the period were numerous and intricate. I appreciated getting a view of the grittier side of London during that time. Overall, a good read featuring a mysterious hero. Mature readers only.