Well.
The Paris Enigma - more 'literary' in a ladies book club sense of the word - you can read it and talk about the philosophy of crime according to De Santis, and pretend you actually read philosophy.
The Alchemy of Murder - more readable in the 'this is actually an enjoyable book to read sense of the word' - you can read it and you actually get a plot to follow along with.
Nellie Bly was a real person back in the 1880's - the first female reporter in America who famously went under cover in a mental asylum to expose the horrific treatment of the inmates. In The Alchemy of Murder, it is during Nellie's stay in Blackwell's Asylum that she discovers a madman who is killing the prostitutes of New York. He escapes the asylum during a fire, but Nellie follows him to London, and then onto Paris where he wreaks havoc during the worlds fair.
You get a real flavour for Paris in the 1880s here - we have anarchists, prostitutes, Louis Pasteur, Oscar Wilde, Jules Verne...the list goes on. Civil unrest! Murder Plots! Slashings! I'm getting hyped up just typing this!
My only problem with this book is the slight weirdness of using real historical characters and playing with them for the sake of your plot. I can't imagine Louis Pasteur ever imagined he would turn up in a historical murder mystery 100 years down the track. Plus, there is this whole weird romance which develops between Nellie and Jules Verne. Jules Verne as a romantic lead is a little much for me to swallow quite frankly.
However weird romance aside, this book is one to delve into if you are after a good historical mystery, with an interesting plot, interesting anarchists, and a 1880s feminist heroine with a vendetta against a murdering psychopathic maniac.
7/10