Dust and shadows - Lyndsay Faye

In Dust and Shadow Sherlock Holmes hunts down Jack the Ripper with impeccably accurate historical detail, rooting the Whitechapel investigation in the fledgling days of tabloid journalism and clinical psychology. This astonishing debut explores the terrifying prospect of hunting down one of the world's first serial killers without the advantage of modern forensics or profiling.
Sherlock's desire to stop the killer who is terrifying the East End of London is unwavering from the start, and in an effort to do so he hires an "unfortuate" known as Mary Ann Monk, the friend of a fellow streetwalker who was one of the Ripper's earliest victims. However, when Holmes himself is wounded in Whitechapel attempting to catch the villain, and a series of articles in the popular press question his role in the crimes, he must use all his resources in a desperate race to find the man known as "The Knife" before it is too late.
Penned as a pastiche by the loyal and courageous Dr. Watson, Dust and Shadow recalls the ideals evinced by Sir Arthur Conan Doyle's most beloved and world-renowned characters, while testing the limits of their strength in a fight to protect the women of London, Scotland Yard, and the peace of the city itself.