The Beast of Chicago: The Murderous Career of H. H. Holmes - Rick Geary
I'd seen this one in the library but didn't think much of it until after I'd read The Devil in the White City, in which Holmes played the title role. Geary seems to have a thing for morbid subjects: he has an entire series of graphic novels called "A Treasury of Victorian Murder." Holmes was a charming doctor who somehow managed to commit insurance fraud, marry three wives, and murder an indefinite number of people. Geary's graphic novel follows Holmes as he sets up shop in Chicago and builds his "Castle," the hotel he used as a murder factory.
The book doesn't necessarily add much information that wasn't in The Devil in the White City, but Geary's illustrations and diagrams do help in picturing the layout of the Castle and some of the features of the World's Fair. However, Geary isn't much of a mystery writer: Larson's book follows Frank Geyer, a detective who was assigned to find some missing children, and ends up retracing Holmes' travels. Geary, instead, follows Holmes and outlines his exploits and murders in a straightforward fashion, which may be good reporting but doesn't generate much suspense.
It's an interesting companion to The Devil in the White City, but is a little weak as a stand-alone book.