These are very, very good historical cozy mysteries and there are 26 of them so far!  I’ve only read 6, but I’m not going to hurry through them.   I know I’ll need a change of pace from time to time.

The plots are twisty driven by strong main characters plus the reader gets immersed in the fascinating (to me) historical setting of Gilded Age New York.  It’s more than a setting because it’s dynamic so parts of it affect the characters and how they live.  A few of the prominent historical characters even become speaking characters in this fiction.   (But the history never overwhelms the plot – a plus.) 

Murder on Marble Row
by Victoria Thompson 
2004 
Read by Callie Beaulieu 8h 12m
Rating:  A+  / historical mystery series – cozy 
(#6 in Gaslight Murders series) 

From the author’s website: 
When an explosion kills wealthy industrialist Gregory Van Dyke, Police Commissioner Teddy Roosevelt presumes that anarchists are responsible and personally asks Detective Sergeant Frank Malloy to track them down. Malloy is up to the challenge—but he faces a different kind of challenge when he encounters Sarah Brandt paying a condolence call on the Van Dykes. Faced with the impossibility of ever expressing his true feelings for Sarah, Frank had vowed never to see or work with her again.

For her part, Sarah is glad to be working with Malloy once again in his hunt for a dangerous killer—though they clash over his conviction that the murder was politically motivated. Frank would like to dismiss her concerns, but whether he likes it or not, he needs Sarah’s help because as she knows—and he is about to discover—the marble facades of Fifth Avenue hide as many dark and twisted secrets as any tenement on the Lower East Side.

On the downside, the narrative seemed to drag toward the very end, but other than that this is the best in the series so far and I’ll keep reading them for awhile anyway.