It's the cover from George Mann's new book. It's got a great Late Victorian, steampunk, playbill, circus poster look to it. It's not released yet, but can be pre-ordered through it's independent publisher, Snowbooks.
According to the website, it's the first in a series hoping to appeal to fans of steampunk, alt-history SF, Jim Butcher fans and Dr. Who fans:
The Affinity Bridge is the first novel in a projected series detailing the adventures of Victorian special agent Sir Maurice Newbury and his delectable assistant Miss Veronica Hobbes. The novel is set in an alternative version of Victorian London in which the industrial age has come early and steam technology has revolutionised the British Empire. Victoria is kept alive on the throne by a primitive life support system and her agents do battle with the enemies of the Crown, both physical and supernatural. The Affinity Bridge follows Newbury and Hobbes as they investigate the wreckage of a crashed airship and its missing automaton pilot, whilst attempting to solve a string of strangulations attributed to a mysterious 'glowing policeman' and deal with a zombie plague that is ravaging the slums of the capital.