Acceptable Loss (2011) by Anne Perry

A William Monk Novel

Following just after the events of Execution Dock, Monk is called to the body of a murdered man in the mud on the banks of the Thames.  The victim is a known criminal, Mickey Parfitt.  Monk traces him to another ship where young boys are imprisoned and used for immoral purposes.  Hester and Monk have taken Scruff, a mud lark, into their home, and are determined to protect him from further abuse.  Also, they suspect that Rathbone's father-in-law is the financier behind the trade in pornography and abuse of boys.  Hester, Margaret (Lady Rathbone), Monk and Rathbone are at odds in the subsequent case against Mr. Ballinger (Margaret's father).

Perry is a master of the Victorian era, placing Monk, Hester, Margaret, and Oliver among the most severe social issues of the day.  Complex plots, in depth characterization, and impeccable writing make Perry's Inspector Monk novels impossible to put down.