Dan Simmons is probably the most unpredictable among my favorite authors. All I know going in is that I will award it somewhere between one and five stars. 
 I'm setting on three this time. The Terror and The Abominable are two of my favorite Simmons novels. Both are historical fiction more than anything else and The Fifth Heart is written in the same vein. 
 I've never been a big fan of Sherlock Holmes which is a big part of the reason I didn't enjoy this but the main reason I was disappointed is the because of the excessive historical fiction itself. The research is beyond thorough and Simmons proceeds to share every last detail of the information he dug up. Lots of stuff we simply do not need to know. At one point he spends over a page discussing the transit system from PA to NY to NJ in detail, why some trains go to some places and not others, etc. I wish he just said "My characters took a train someplace" and then moved on with the story. I felt like I was getting bludgeoned by the research at the expense of the plot, which by the way, was pretty weird to begin with. 
 Final thoughts: Well written but could have been shaved a few hundred pages.