April-May 1901. Crossings, the second novel of the series, is set in the spring of 1901, a time when Brooklyn's own Willoughby Street was more than a match for Manhattan's Tammany Hall. Harry is looking for a link between the apparent suicide of an insurance agent and the untimely deaths of two of his clients. He must seek out gambling parlors, a house of assignation and other dens of vice, while being misled by corrupt cops and opportunistic con men. Meanwhile, Emmie aids the investigation in her usual inimitable way.
A Crib Sheet is available which includes a short glossary, a list of the characters, and a general map of the area. (also available as DOC or PDF)
Online map: I've created a Google map with most of the book's locations indicated.
Several posts on my blog touch on subjects mentioned in this story. And there's a glossary, a chronology, and a list of characters for the books.