The Mysteries of London is a "penny blood" classic. There are many plots in the story, but the overarching purpose is to reveal different facets of life in London, from its seedy underbelly to its over-indulgent and corrupt aristocrats. The Mysteries of London are considered to be among the seminal works of the Victorian "urban mysteries" genre, a style of sensational fiction which adapted elements of Gothic novels - with their haunted castles, innocent noble damsels in distress and nefarious villains - to produce stories which instead emphasized the poverty, crime, and violence of a great metropolis, complete with detailed and often sympathetic descriptions of the lives of lower-class lawbreakers and extensive glossaries of thieves' cant, all interwoven with a frank sexuality not usually found in popular fiction of the time.