This is the first book in Anne Perry's long-running Thomas Pitt series, but it was conceived as a standalone novel, which is a key aspect of its unusual tone. The detective and eventual series protagonist is at best a secondary character. The focus instead is on the Ellisons, who live in a neighborhood where a serial killer is targeting young women. The detective element is played down; there's much emphasis on how impossible it is to investigate this kind of insanity-driven violence with the tools available in the late 19th century. Possible suspects are gradually eliminated by the absence of opportunity, but The Cater Street Hangman is not so much a murder mystery as an exploration of the effects of proximity to murder on a late Victorian family. On those terms it's an enjoyable if slow-paced novel.
The brutal fact of violent crime is bound to shatter the hypocrisy and secrecy on which the patriarchal order of the Victorian household was based. The Ellisons are forced to confront the possibility that one of them might be a murderous lunatic. This acceptance of the ugly side of life forces to the surface several smaller secrets and buried conflicts, leaving the family raw... and yet, perhaps, better off than they were before. Perry does a fine job of elaborating the constricted emotional lives of Victorians, and in particular of Victorian women, without reducing any of the characters to caricature. The father is no demanding ogre but an ordinary man raised with deeply sexist and authoritarian expectations. Even the sharp-tongued grandmother, something of a stock figure in contemporary 19th-century stories, is not without her pitiable side, though the austere and arrogant vicar remains one-dimensional.
The emphasis on emotional nuance and on slow-building despair mean that this is not an especially lively novel for those who don't enjoy simmering interpersonal tension as much as I do. But Perry's simple yet graceful prose sustains it, as does a comic subplot involving one daughter's pursuit of a marriage proposal from a rakish gentleman. Indeed, this is as much an unconventional romance novel as an unconventional murder mystery. That very difficulty of classification is part of the charm of The Cater Street Hangman, which offers the pleasures of period mystery, period romance, and period drama without becoming too bound by the formulas of any. Whether further volumes in the series will maintain this unique character I can't say, but on its own terms this is a surprisingly taut and engaging novel.