THE PROVIDENCE RIDER (Robert R. McCammon)

Synopsis of "The Providence Rider", fourth book of "Matthew Corbett" by Robert R. McCammon:  In the winter of 1703, with Matthew still haunted by his lethal encounter with notorious mass murderer Tyranthus Slaughter. When an unexplained series of explosions rocks his Manhattan neighborhood, Matthew finds himself forced to confront a new and unexpected problem. Someone is trying and trying very hard to get his attention. That someone is a shadowy figure from out of Matthew's past: the elusive Dr. Fell. The doctor, it turns out, has a problem of his own, one that requires the exclusive services of Matthew Corbett.
The ensuing narrative moves swiftly and gracefully from the emerging metropolis of New York City to Pendulum Island in the remote Bermudas. In the course of his journey, Matthew encounters a truly Dickensian assortment of memorable, often grotesque, antagonists. These include Sirki, the giant, deceptively soft-spoken East Indian killer, Dr. Jonathan Gentry, an expert in exotic potions with a substance abuse problem of his own, the beautiful but murderous Aria Chillany, and, of course, the master manipulator and "Emperor of Crime" on two continents, Dr. Fell himself.