By cleansing the archival records of the cobwebs of biases and officialese which shroud their language and style, the modern historian can plumb to their depths the dark nooks and corners of the underworld of colonial Calcutta, and look at them from a fresh angle. It will raise a number of queries about colonial criminology - Who were the criminals in 19th century Calcutta? How were they made? What was the nature of their crimes? To what extent did they bring forth the colonial penal system, and in what measure did this newly organised system of detection, prosecution and punishment, in its turn, create new types of crime? This essay attempts to wrestle with these questions and suggests a few explanations while inviting responses from historians engaged in research in the field.