Batman meets steampunk with slight touch of Lovecraft, set in 1920s Prohibition New York Ghosts of Manhattan by George Mann has all of these features. Coal-powered cars travel the street; a Cold War between America and the British Empire; and Roman Coins in mint condition appearing at crime scenes - you have an interesting book.
The Ghost is a vigilante hero, whose alter-ego is playboy haunted by 'things' he saw during war including something that he can't explain - so there is the Batman/The Shadow link. People are dying and crimes being committed by a gang headed by The Roman. Who the Roman is? Why is he called the Roman? What are these people dying? These questions are explained with a touch of creatures from another dimension throw in for good measure.
This is a good fun book, that I kept thinking would make an great graphic novel; like a lot of steampunk the images are strong. Well paced action and story, that keeps the readers interest.
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