In nineteenth-century London, middle-class women did not engage in what were seen as "unladylike activities." There were many jobs that a woman simply could not be expected to do because they were viewed as unsuitable for finer female sensibilities. The idea of a woman being involved in the murkiness of criminal detection must have seemed a radical and adventurous one in Victorian times: women simply did not do that sort of thing. And yet, in 1864,...