I bought this at a library sale because the cover caught my eye; I had no expectations, as I'd never heard of it before but it had a vaguely Holmesian feel to it.
I wasn't wrong; there are both subtle and blatant nods to Doyle and Holmes throughout the story, but... I don't know how to say this. The Mangle Street Murders reads like it was written by someone well-versed in the Holmes cannon but who resented the varnish put on the Victorian age and so set out to reimagine a Holmes worthy murder mystery in all its gory, gritty detail.
If that's indeed what Kasasian set out to do, then boy howdy did he/she succeed. Sydney Grice, the famous personal detective is what Holmes might look like if he were actually a sociopath. Self admittedly greedy, vain, selfish and without a shred of courtesy or decency he's almost a comic figure, until the reader is forced to witness his delight in public executions and other examples of his inhumanity. The author tries half-heartedly to hint at some underlying decency, but frankly fails; they are too few and too brief to have any impact. Add to that the grisly, graphic details in just about every scene of the book and it's a wonder I kept reading past the first mortuary scene. There were times I honestly felt like the author was trying to punish the reader, beating them over the head with the reality of the 1880's.
But I did keep reading; I really liked the MC, March Middleton. From the introduction it's clear she's Grice's historian, in much the same way Watson was for Holmes, only she is (sorry Watson, I love you) much smarter than Watson and a far more invested participant. Of course she has a hidden pain - a tragedy in her past - that is shared piecemeal in the form of old journal entries. These are done perfectly: just often enough that they tug at your soul and keep you on the edge of your seat dreading what must be the inevitable. The inevitable, however, must be part of a multi book story arc because we don't get to it here.
The plotting was competent. Of course Grice is secretive so neither Marsh nor the reader are every privy to crucial details until very nearly the end when he waves his superiority around in a nauseating way, but Marsh gets hers back, making for a more even read. The ultimate criminal was a person I pegged very early in the book, but there were so many layers and complexities that really all I'd done was identify the tip of the iceberg.
All said, the writing is excellent, the story and characters were compelling and I definitely won't read the second one. I'm not at all ashamed to admit that I don't want this level of factual realism in my books. I enjoyed the mystery but it was overshadowed by the author's need for verisimilitude; if you don't mind that level of grittiness, and you enjoy a good historical mystery, then this one is worth exploring. Otherwise stick with Holmes and Watson.